Answer:
C
Step-by-step explanation:
First, find out how many games they won:
x/15 = 80/100
Cross multiply
x × 100 = 15 × 80
100x = 1200
x = 12
They won 12 out of 15 games
Second, find out how many wins out of 30 games are needed to have a 90% winning percentage
x/30 = 90/100
Cross multiply
x × 100 = 30 × 90
100x = 2700
x = 27
27 game wins are needed to have a 90% winning percentage
Lastly, find the difference between 27 wins (total needed) and 12 wins (total number of wins they currently have)
27 - 12 = 15
They need to win 15 more games to have a 90% winning percentage
