Question

Ben solved a fraction division problem using the rule “multiply by the reciprocal.” Look at his work.

StartFraction 7 Over 20 EndFraction divided by two-fifths. StartFraction 20 Over 7 EndFraction times two-fifths = StartFraction 40 Over 35 EndFraction = StartFraction 8 Over 7 EndFraction = 1 and StartFraction 1 Over 7 EndFraction

Did he solve the problem correctly?
Yes. He solved the problem correctly.
No. He multiplied the dividend by the divisor.
No. He multiplied the denominators instead of finding a common denominator.
No. He multiplied with the reciprocal of the dividend instead of with the reciprocal of the divisor.

Answer 1

Answer:

  (d)  No. He multiplied with the reciprocal of the dividend instead of with the reciprocal of the divisor.

Step-by-step explanation:

The problem should have been written ...

  $\dfrac{7}{20}\div\dfrac{2}{5}=\dfrac{7}{20}\times\dfrac{5}{2}\qquad\text{the reciprocal of the divisor is used}$

Instead, Ben wrote it as ...

  $=\dfrac{20}{7}\times\dfrac{2}{5}\qquad\text{the reciprocal of the dividend is erroneously used}$

_____

Additional comment

Ben will get the reciprocal of the proper answer: 8/7 instead of the correct value of 7/8.

Answer 2

Answer:

D)  No. He multiplied with the reciprocal of the dividend instead of with the reciprocal of the divisor.

Step-by-step explanation: