After working 4 hours, Frank has made 21 machine parts. At the same rate, how many parts can he make in 7 hours?
A) (21/4)*7
B) 7(21)
C) 7(4) /21
D) 7(4)(21)
solve
21/4 = x/7
To find out how many parts Frank can make in 7 hours, we need to determine the rate at which he produces parts.
We know that in 4 hours, he made 21 parts. To find his hourly rate, we divide the total number of parts (21) by the number of hours (4):
Hourly rate = Total number of parts / Number of hours
= 21 / 4
= 5.25 parts per hour
Now that we know his hourly rate, we can calculate how many parts he can make in 7 hours by multiplying his hourly rate by the number of hours:
Number of parts in 7 hours = Hourly rate * Number of hours
= 5.25 parts per hour * 7 hours
= 36.75 parts
Rounding to the nearest whole number, Frank can make approximately 37 parts in 7 hours.
The correct answer choice is not provided, but if we evaluate the options:
A) (21/4)*7 = 5.25 * 7 = 36.75 parts (approximately 37 parts)
B) 7(21) = 147 parts
C) 7(4) / 21 = 1.33 parts (not possible, as it is not a whole number)
D) 7(4)(21) = 588 parts
None of the given answer choices match the correct answer, which is approximately 37 parts.