Maths Percentage
posted by Zayn on .
After spending 30% of his money, John had $140 left. How much did he have at first.
Siti and Ali saved $4500. Ali and Jim saved $2950. Siti saved thrice as much as Jim. How much did Ali save?
At a concert, there were 15 more children than adults. Each child paid $5 each and each adult paid $10 for a ticket. If the total amount of money collected from them was $150, how many children were there?

1. (1.30)x = 140
3. C = A + 15
5C + 10A = 150
Substitute A+15 for C in second equation and solve for A. Insert that value into the first equation and solve for C. Check by inserting both values into the second equation.