Question

#15. As a math teacher you are emphasizing fractions and decimals this week. You ask your students to add: 2 over 5 plus 7 over 8. Express as decimal answer.

Select an Answer
If you would like to eliminate an answer choice, click the icon to the left of the option.


A
0.40


B
0.875


C
0.90


D
1.275


E
1.375

Answer 1

To add the fractions \(\frac{2}{5}\) and \(\frac{7}{8}\), we first need to find a common denominator. The least common multiple of 5 and 8 is 40.

Now we convert each fraction:

1. Convert \(\frac{2}{5}\) to a fraction with a denominator of 40:
\[
\frac{2}{5} = \frac{2 \times 8}{5 \times 8} = \frac{16}{40}
\]

2. Convert \(\frac{7}{8}\) to a fraction with a denominator of 40:
\[
\frac{7}{8} = \frac{7 \times 5}{8 \times 5} = \frac{35}{40}
\]

Now we can add the two fractions:
\[
\frac{16}{40} + \frac{35}{40} = \frac{16 + 35}{40} = \frac{51}{40}
\]

Next, we need to convert \(\frac{51}{40}\) to a decimal:
\[
51 \div 40 = 1.275
\]

Thus, the decimal answer is:
**D. 1.275**