Mental Math
48x5
240
Solve 5(2x - 3) = 3(3x + 1)
x = 18
A fair die is rolled twice. What is the probability the sum is 9?
1/9
Solve (x - 9)(x + 5) = 0
x = 9 or x = -5
Arithmetic sequence: a1 = 7, d = -3. Find the 5th term (a5).
-5
125/0.25
500
Solve:(12x3 y-1) / (4x-1 y2)
3x4y-3 or 3x4/y3
A bag has 3 red, 4 blue, and 5 green balls. One is chosen. What is the probability it is NOT green?
7/12
A ball is thrown. Its height is h(t) = -5t^2 + 30t + 2. What is the MAXIMUM height?
47
Sequence: a1 = 4, a12 = 37. Find the common difference (d).
3
A number is decreased by 20% and becomes 96. What was the original number?
120
Solve for x: (x-5)/4 + (2x+1)/6 = 3
x = 7
Two cards are drawn from a standard deck WITHOUT replacement. Probability both are face cards (J, Q, K)?
11/221
The area of a rectangle is 90. The sides are x and (2x + 3). Solve for positive x.
x = 6
Find the sum of the first 25 terms where a1 = 12 and d = 5.
1800
3/7 of 350
150
Solve the system for x and y:
3x - 2y = 9
4x + y = 23
x = 5, y = 3
A box has 6 defective and 14 good parts. Two are drawn without replacement. Probability AT LEAST ONE is defective?
99/190
Rocket height: h(t) = -5t^2 + 45t + 50. When does it hit the ground (h = 0)?
10 seconds
Arithmetic sequence: a8 = 45 and a20 = 93. Find the common difference (d).
4
63^2 -37^2
2600
Solve for positive x:
10/x = x - 3
x =5
A drawer has 5 white, 4 black, and 3 red socks. Two drawn randomly. Probability they are the SAME color?
19/66
The sum of two consecutive integers is 41. Their product minus 20 is a perfect square. Find the integers.
20 and 21
The sum of the first 15 terms is 570. If d = 4, find the first term (a1).
10