Question

Bob believes his test grade varies directly with the number of hours he spends studying and inversely with the number of hours he spends playing baseball. On his first​ test, he spent 7 hours studying and 4 hours playing baseball and scored a 42. What score should he expect on his second test if he studies 5 hours and plays baseball for 3 ​hours?

Answer 1

Answer:

40

Step-by-step explanation:

• Study- s=7 hrs,
• Play- p=4 hrs
• Score- 42

Score varies directly with hours of study and inversely with hours of play so the score has a coefficient x as:

• score=x*s/p

Applied to first test we get:

• 42=x*7/4 => x=42*4/7=24

Now we got the coefficient of 24 which should be same for the second test

If we apply same to second test, then:

• Study- s=5 hrs,
• Play- p=3 hrs
• score= 24*5/3= 40

So expected score is 40