The number a is 70 % less than the positive number b . The number c is 80 % greater

Question

The number a is 70 % less than the positive number b . The number c is 80 % greater than a . The number c is how many times b ?

Accepted Answer

The correct answer is .54 . It's given that the number a is 70 % less than the positive number b . Therefore, a = 1 - 70 100 b , which is equivalent to a = 1 - 0.70 b , or a = 0.30 b . It's also given that the number c is 80 % greater than a . Therefore, c = 1 + 80 100 a , which is equivalent to c = 1 + 0.80 a , or c = 1.80 a . Since a = 0.30 b , substituting 0.30 b for a in the equation c = 1.80 a yields c = 1.80 0.30 b , or c = 0.54 b . Thus, c is 0.54 times b . Note that .54 and 27/50 are examples of ways to enter a correct answer.

Question the-nu