Question

Sari has 3 times as many pencil erasers as Sam. Together, they have 28 erasers. How many erasers does Sari have?

Answer 1

Let

x--------> amount of erasers that Sari has

y--------> amount of erasers that Sam has

we know that

$x=3y$-------> equation $1$

$x+y=28$-----> equation $2$

Substitute equation $1$ in equation $2$

$[3y]+y=28\\ 4y=28\\ y=28/4\\ y=7$

find the value of x

$x=3y\\ x=3*7\\ x=21$

therefore

the answer is

Sari has $21$ erasers

Answer 2

She has 25 erasers.
28
- 3
-----
25