Asingle gram of a certain metallic substance has 0.52 gram of copper and 0.26 gram of zinc. the remaining portion of the substance is nickel. ben estimated that 0.2 gram of nickel is in 1 gram of the substance. he used this to estimate the amount of nickel in 35 grams if substance. find the result of bens estimation strategy. then find the exact amount of nickel in 35 grams of the substance.

First off all, if we have 1 gram of a substance that has 0.52 gram of copper and 0.26 gram of zinc, the remainder will be: 
Since we know that the remaining portion of the substance is nickel, we have 0.22 gram of nickel.

Now, Ben estimates that 1 gram of the substance has 0.2 gram of nickel. To find how many grams of nickel are in 35 grams of the substance, we are going to multiply the grams of the substance by the gram of nickel:

We can conclude that according to Ben, 35 grams of the substance has 7 grams of nickel.

But we know that in 1 gram of the substance are not 0.2 gram of nickel but 0.22. So lets multiply the grams of the substance by 0.22 to find the actual grams of nickel in it:

We can conclude that 35 grams of the substance has 7.7 grams of nickel.