Question

Giovanna used the calculations below to determine the height of a stack of 7 books that are each 2 5/8

inches thick what
was her error?
C. There should be a subtract step not an addition step
D. Two should have been multiplied by 5/8

Answer 1

Answer:

Option C. Seven was not multiplied by 5/8

Step-by-step explanation:

we know that

To determine the height of a stack of 7 books that are each 2 5/8  inches thick. multiply 7 by 2 5/8

so

$7(2\frac{5}{8})\\ \\7(2+\frac{5}{8})\\ \\7*2+7*\frac{5}{8}\\ \\14+\frac{35}{8}\\ \\14+4+\frac{3}{8}\\ \\18\frac{3}{8}\ in$

therefore

Seven was not multiplied by 5/8

Answer 2

Answer:

Option B.

Step-by-step explanation:

Giovanna did the calculations to determine the height of a stacks of 7 books having $2\frac{5}{8}$ inches thickness of each book.

$7(2\frac{5}{8})$

$=7(2+\frac{5}{8})$

$=(7\times 2)+7(\frac{5}{8})$

$=14+\frac{35}{8}$

$=14+4+\frac{3}{8}$

=18+$\frac{3}{8}$

$=18\frac{3}{8}$

Now when compare this solution with Giovanna's solution we find error in 3rd step, in which she hasn't mutiplied the fraction $\frac{5}{8}$ by 7.

Therefore, option B is the correct one.