Percent Equation
Use the percent equation to solve:
What is 25% of 600?
x = 0.25(600)
x = 150
Use the percent proportion to solve
45 is what percent of 90?
45/90 = x/100
90x = 4500
x = 50%
The team that gets this correct chooses a team to REMOVE 100 points from.
Andy used to earn $20 an hour to teach piano lessons. He raised his price to $24 per hour. What is the percent increase in his hourly fee?
CHANGE: 24 - 20 = 4
4/20 = 0.2
20% increase
This morning, I heard the weather was going to be a high of 43 degrees. The actual high was 50 degrees. What is the percent error of the estimated temperature?
DIFFERENCE: 50-43 = 7
7/50 = 0.14
0.14(100)= 14% error
Nancy invested $6000 in a bond at a yearly rate of 3%. How much interest will Nancy earn after 8 years?
I = 6000(0.03)(8)
I = $1440
Use the percent equation to solve
247 is 65% of what number?
247 = 0.65(x)
247/0.65 = x
380 = x
Use the percent proportion to solve
23% of 75 is what number? NO ROUNDING
x/75 = 23/100
100x = 1875
x = 17.25
The price of a shirt is $18.50, but you have a coupon that lowers the price to $12.95. What is the percent of change that the coupon offers?
CHANGE: 18.50 - 12.95 = 5.55
5.55/18.50 = 0.3
0.3(100)= 30% decrease
Alex thought only 15 people would show up for his party, but 24 people came. What is the percent error of his estimation?
Round to nearest whole percent.
DIFFERENCE: 24 - 15 = 9
9/24 =0.375
0.375(100) = 37.5%
ROUNDED --> 38%
The team that gets this correct chooses a team to REMOVE 200 points from.
A bank is offering 2.5% simple interest on a savings account. If you deposit $5000, how much interest will you earn in 3 years?
I = 5000(0.025)(3)
I = $375
DOUBLE POINTS!!! Use the percent equation to solve
Jose spent $2 of his allowance on baseball cards. His allowance is $10. What percent of his allowance did he spend on baseball cards?
2 = 10x
2/10=x
0.2(100)= 20%
Use the percent proportion to solve
What percent of 77 is 7? ROUND to nearest whole percent
7/77 = x/100
77x = 700
x = 9.09... = 9%
In June, Ryan earned $20 mowing lawns. He made $35 mowing lawns in July. What is the percent of change in his earnings?
CHANGE: 35-20 = 15
15/20=0.75
0.75(100) = 75% increase
Greyson predicted he would score 20 points in a basketball game, but he actually scored 22 points. What is the percent error in his prediction? ROUND to the nearest whole percent.
DIFFERENCE: 22-20 = 2
2/22 =0.0909...
0.09(100) = 9% error
John’s parents deposited $1000 into a savings account as a college fund when he was born. How much will John have in this account after 18 years at a yearly simple interest rate of 17.25%?
I = 1000(18)(0.1725)
I = 3105
TOTAL = 3105 + 1000 = $4105
Use the percent equation to solve
You and your friend babysat the neighbor's kid for $60 total. You agreed to give 40% of your earnings to your friend for helping you out. How much money did you keep?
x = 60(0.6)
x = $36
DOUBLE POINTS!! Use the percent proportion to solve
A survey showed that 62% of middle school students participate in after school activities. If there are about 1050 students at HJHS, how many students are predicted to NOT participate in those activities?
x/1050=62/100
100x = 65100
x = 651
1050 - 651 = 399 students NOT participating
The original price of a pair of jeans was $40. The price was marked down to $35. What is the percent of change in the price?
ROUND to nearest whole percent.
CHANGE: 40 - 35 = 5
5/40 = 0.125
0.125(100) = 12.5%
ROUNDED--> 13% decrease
Jessie estimates the weight of her cat to be 10 pounds. The actual weight of the cat is 13.75 pounds. What is the percent error of her estimation? ROUND to the nearest whole percent.
DIFFERENCE: 13.75 - 10 = 3.75
3.75/13.75 = 0.2727...
0.2727(100) = 27.27%
ROUNDED -->27% error
Jenna’s brother borrowed $200 from her to buy a tablet. She will charge him 3% simple interest. Her brother says he will pay her back in 6 months. What is the total amount he will pay back?
I = 200(0.03)(0.5)
I = $3
TOTAL = 200 + 3 = $203
Use the percent equation to solve
Because the popularity of outlet malls has recently declined, about 300 of the 1800 traditional retail malls across the United States may close in the next few years. Find the percent of retail malls that may close. ROUND to the nearest whole percent.
300 = 1800x
300/1800 = x = 0.166...
0.166(100) = 16.6%
ROUNDED --> 17%
Use the percent proportion to solve:
The LA Rams WON 12 out of 17 games last season. What percent of games did they LOSE? Round to nearest whole percent.
5/17 = x/100
17x = 500
x = 29%
Last week you had $240 in your bank account, but this week you have $320. Find the percent of change.
ROUND to nearest whole percent
CHANGE: 320-240 = 80
80/240 = 0.333...
0.333(100) = 33.3%
ROUNDED --> 33% increase
My phone estimated 5 hours left until it is fully charged. It actually took 4.35 hours to charge. Find the percent error.
ROUND to the nearest whole percent.
DIFFERENCE: 5 - 4.35 = 0.65
0.65/4.35 = 0.1494...
0.149(100) = 14.9%
ROUNDED --> 15% error
Mr. Johnson borrowed $8000 to make home improvements with an interest rate of 18.5%. What is the total amount that Mr. Johnson has to pay back after the 3 years and 6 months?
I = 8000(0.185)(3.5)
I = 5180
TOTAL = 8000 + 5180 =$13180