Sam had 70 erasers and rulers. after giving away 1/3 of his erasers and 10 rulers, he had an equal number of erasers and rulers left. how many erasers did he have in the beginning?

36 erasers

Step-by-step explanation:

Let number of erasers be e

let number of rulers be r

We can write:

e + r = 70

and

After giving away, he has

Erasers:  2/3e

Rulers:  r - 10

These two are equal, so we can write and solve:

2/3e = r - 10

2/3e + 10 = r

Putting this in initial equation, we have:

e + (2/3e + 10) = 70

5/3e + 10 = 70

5/3 e = 60

e = 36

And rulers is:

r = 2/3(36) + 10 = 34

Hence, he had 36 erasers in the beginning