Phil ate $2/5$ of a pizza, Caroline ate $1/4$ of a pizza. How much did they eat in all?

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Answer 1 · 2018-03-24T16:45:52

$13/20$ of a pizza

Convert each fraction so that it has a common denominator. 5 and 4 are common factors of 20, so let's use 20 in the denominator.

$2/5=2/5*1=2/5*4/4=8/20$

$1/4=1/4*1=1/4*5/5=5/20$

Now it's easy to add them:

$8/20+5/20=13/20$

Answer 2 · 2018-03-24T16:46:56

Phil and Caroline ate $13/20$ of the pizza in all.

The lowest common multiple of $5$ and $4$ is 20.

$20/5 = 4$
Multiplying the numerator and denominator of $2/5$ by $4$ :
$(2*4)/(5*4) = 8/20$

$20/4 = 5$
Multiplying the numerator and denominator of $1/4$ by $5$ :
$(1*5)/(4*5) = 5/20$

Now that both fractions have the same denominator, we can add their numerators and keep the same denominator.
$2/5 + 1/4 = 8/20 + 5/20 = 13/20$

Phil ate 2/52/5 of a pizza, Caroline ate 1/41/4 of a pizza. How much did they eat in all?