9514 1404 393
Answer:
C. 13
Step-by-step explanation:
Put 4 where y is in the equation and do the arithmetic.

She burns 250 by herself and she burns 3 times as many with her sister.
Multiply the calories by herself by 3:
250 x 3 = 750
Now you need to multiply that by the number of hours.
The formula is a. t[c(h)] = 750h
The answer is 10.5, but don't put 10.5 if it's just asking for the number and not the unit only put (10)!!!