Question

Sara has 400 marbles. if she gives $\dfrac{1}{5}th$ of her marbles to Sam and Sam gives $\dfrac{3}{4}th$ of his marbles to David, then how many marbles does Sam have left?

Answer 1

Hint: A fraction is a unit of measurement that represents a piece of something larger. It represents the whole's equal pieces. We will calculate the $\dfrac{1}{5}th$ of 400 that Sara will give to Sam. Calculate the $\dfrac{3}{4}th$ of Sam's marbles to know how much he gave to David.

Complete step by step answer:
We have given the total number of marbles Sara has. We will first find the number of marbles Sam get and then find the number of marbles Sam left after giving it to David.
We have given total number of marbles = 400
We know that Sara gives $\dfrac{1}{5}th$ of total marbles to Sam.
The number of marbles Sam get $ = \dfrac{1}{5} \times 400$
The number of marbles Sam get = 80
We know that Sam gives $\dfrac{3}{4}th$ of his total to David.
The number of marbles David get $ = \dfrac{3}{4} \times 80$
The number of marbles David get = 60
The numbers of marbles have left with Sam
= The number of marbles Sam get - The number of marbles David get
=80-60 marbles
=20 marbles
The number of marbles left with Sam=20

Note:
We can also solve this question in another way. Instead of finding the number of marbles Sam gives to David. We will find the parts of marbles left with Sam after giving to David then find the number of marbles left with David.