Question

Jessie was given the problem 3 2/5÷3/10=to solve. Jessie’s work looks like this:

3 2/5÷3/10=
17/5÷3/10=
175⋅310=17⋅3/5⋅10
51/50=1 1/50

Jessie’s answer is incorrect. Answer the following questions about Jessie’s work.
Find and describe Jessie’s error.
What is the correct answer?

Answer 1

Find and describe Jessie’s error.
- Jessie converted 3 2/5 correctly to 17/5, but then treated ÷ 3/10 as multiplying by 3/10 instead of multiplying by its reciprocal. When dividing by a fraction you must multiply by the reciprocal (flip the divisor). Jessie did 17/5 × 3/10, which produced 51/50; that is the wrong operation.

What is the correct answer?
- Do the correct operation: (17/5) ÷ (3/10) = (17/5) × (10/3).
- Simplify: (17 × 10)/(5 × 3) = 170/15 = 34/3 = 11 1/3.

So the correct answer is 34/3 (or 11 1/3).