A single gram of a certain metallic substance has 0.52 g of copper and 0.25 g of zinc the remaining portion of the substance is nickel been estimated that 0.2 g of nickel is in 1 g of the sub since he use this to estimate the amount of nickel and 35 g of the substance find the result of Ben’s estimation strategy then find the exact amount of the nickel in 35 g of nickel in 35 grams of the substance

Ben's estimate gives 7 g of nickel; the actual amount is 8.03 g.

In 1 g of the substance, there is 0.52 g of copper and 0.25 g of zinc; this gives 
0.52+0.25 = 0.77 g of the substance.

The remaining part of the substance is nickel:
1-0.77 = 0.23 g of nickel.

Using Ben's estimate, 0.2 g of nickel per gram of substance, we have
0.2(35) = 7 g of nickel in 35 g of the substance.

The actual amount is 0.23(35) = 8.03 g of nickel in 35 g of the substance.