## [SOLVED] Maths Historgram help

MathQ.jpg picture by jsmith613 - Photobucket

The histogram shows info about the masses, in grams, of some stones.
There are 120 stones with masses less that 30g
Calc an estimate for the number of stones with a mass beween 35 & 70 g

(this is GCSE Mock revision - NOT HOMEWORK)

My exam is tomorrow