Petrus shared his birthday cake with 5 of his friends.He gave Sandy 1/8,Mary and Paul1/10 each.He gave Jack 1/5 and Sandra 3/20.What fraction of the cake had he left.
1/8 = 5/40
1/10 = 4/40
1/5 = 8/40
3/20 = 6/40
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. . . 23/40 >>>> eaten
40/40 - 23/40 = 17/40 left
To find the fraction of the cake that Petrus had left, we need to calculate the sum of the fractions given to his friends and subtract it from 1 (since the sum of the fractions given to his friends represents the portion of the cake already shared). Let's start by calculating the fractions given to each friend:
Sandy: 1/8
Mary and Paul: 1/10 + 1/10 = 2/10 = 1/5
Jack: 1/5
Sandra: 3/20
Now, let's add up all the fractions given to Petrus' friends:
1/8 + 1/5 + 1/5 + 3/20
To add these fractions, we need to find a common denominator. In this case, the least common denominator is 40:
(5/40) + (8/40) + (8/40) + (6/40) = 27/40
Therefore, Petrus shared 27/40 of the cake with his friends. To find the fraction he had left, subtract this fraction from 1:
1 - 27/40 = 40/40 - 27/40 = 13/40
So, Petrus had 13/40 of the cake left.