Question

Alima is solving a question, where a given number has to be multiplied by 15. Alima did not read the question carefully, and multiplied the number by 5 (instead of 15). If her answer is 150 less than the correct answer, find the given number.

Answer 1

x    -  Alma's given number

15•x  -  the number multiplied by 15 (the correct answer)

5•x   - the number multiplied by Alma (Alma's answer)

her answer is 150 less than the correct answer:

5•x = 15•x - 150

15x - 150 = 5x

15x - 5x = 150

 10x = 150

   x = 15