Number problems

(21) If a number is decreased by 15% of itself, the result is 85. What is the number?

• (a) 90
• (b) 100
• (c) 100 or 85
• (d) 85

Answer

Correct Answer: (c) 100 or 85

Let the number be \(x\).

Given that \(x – 0.15x = 85\), you can solve this equation to find \(x = 100\). However, \(x\) can also be 85, so both are correct answers.

(22) The difference between a number and its square is 90. What is the number?

• (a) 8
• (b) 10
• (c) 11
• (d) 9

Answer

Correct Answer: (d) 9

Given that \(x – x^2 = 90\), you can solve this equation to find \(x = 9\).

(23) The sum of three consecutive odd numbers is 111. What are the numbers?

• (a) 35, 37, 39
• (b) 33, 35, 37
• (c) 35, 37, 39
• (d) 29, 31, 33

Answer

Correct Answer: (c) 35, 37, 39

Let the three consecutive odd numbers be \(x\), \(x+2\), and \(x+4\).

Given that \(x + (x+2) + (x+4) = 111\), you can solve this equation to find \(x = 35\). So, the numbers are 35, 37, and 39.

(24) If the product of two numbers is 180, and one of the numbers is 15, what is the other number?

• (a) 10
• (b) 12
• (c) 12 or 15
• (d) 18

Answer

Correct Answer: (c) 12 or 15

Given that \(15x = 180\), you can solve this equation to find \(x = 12\). However, the other number can also be 15, so both are correct answers.

(25) If a number is divided by 9, the result is 7. What is the number?

• (a) 54
• (b) 49
• (c) 63
• (d) 81

Answer

Correct Answer: (c) 63

Given that \(x/9 = 7\), you can solve this equation to find \(x = 63\).