Question

Which of the following interchanges of signs would make the given equation correct? 8 - 42 + 104 ÷ 13 × 4 = 18

• A. 8 and 42
• B. 104 and 4
• C. 42 and 13
• D. - and +

Answer 1

Answer:

D. - and +

Check the expression:

8 - 42 + 104 ÷ 13 × 4

First solve as it is:
$104 ÷ 13 = 8,\quad 8 × 4 = 32$
$8 - 42 + 32 = -2 \ (\text{not } 18)$

Try interchanging signs

If we interchange ‘−’ and ‘+’:

$8 + 42 - 104 ÷ 13 × 4$

Now solve:
$104 ÷ 13 = 8,\quad 8 × 4 = 32$
$8 + 42 - 32 = 18$

Final Answer: Interchange ‘−’ and ‘+’