Question

Sumanta has $175 in $5 and $10 bills in his drawer. The number of $5 bills is three times the number of $10 bills. How many of each are in the drawer?

Answer 1

21 $5 and 7 $10

Explanation:

set variables first

the number of $5 is x

the number of $10 is y

so then we set equations

175 = 5x+10y

then they tell us another piece of information

x = 3y

then we solve this system by substituting the second equation into the first

175 = 5(3y) +10y

175 = 15y +10y

175 = 25y

y = 7

plugging into second one

x = 21