in a rock collection, 60 percent of the rocks are quartz. If the collection contains 35 rocks how many are quartz

Question

HI im jeremy plz help me fast

Answer 1

Hi Jeremy,

There are multiple ways to do this problem. The first way is to realize that you can translate the phrase "60% of the 35 rocks are quartz" to the number of quartz=0.60 x 35 = 21 of the rocks are quartz.

 

The other way to do this problem is to do a proportion, because 60% is equivalent to 60/100.

Thus, you could say x/35=60/100, and solving the equation for x again yields 21.

 

I think the first way is easier, but this gives you two strategies for solving similar problems.