Question

An MTN cellular-phone user notices that her cellular phone accounts for three
consecutive months were significantly different. In May, her account was one and a half
times more than her account in June. Her account in July was R 50 more than her account in
June. In total, she spent R575 in cellular-phone accounts in the three months. What was her
account for each month?

Answer 1

Let $x$ be the money she spent in June, then in July she spent $(x+50)$, and in May she spent $1.5\times x$. As in total she spent $575$, then

$$1.5\times x +(x+50)+x=575$$

$$3.5\times x = 575-50$$

$$x=150$$

Then in June she spent $150$, in July $150+50=200$, and in May$150\times 1.5= 225$