If the signs ‘+’ and ‘÷’ are interchanged, which of the following equations becomes correct?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → 33 + 11 × 8 ÷ 3 = 27
In each option write ‘÷’ for every ‘+’ and ‘+’ for every ‘÷’, then work out the left side by BODMAS.
Option (4) becomes 33 ÷ 11 × 8 + 3
\(33\div11=3\)
\(3\times8=24\)
\(24+3=27\), which equals the right side
Why the other options are incorrect
Option (1) 16 + 4 – 8 + 3 = 11 — Incorrect. It becomes 16 ÷ 4 – 8 ÷ 3, which is \(4-\frac{8}{3}=\) \(\frac{4}{3}\), not 11.
Option (2) 16 + 4 × 8 + 3 = 45 — Incorrect. It becomes 16 ÷ 4 × 8 ÷ 3, which is \(4\times8\div3=32\div3=\) \(\frac{32}{3}\), not 45.
Option (3) 18 + 7 – 17 + 3 = 38 — Incorrect. It becomes 18 ÷ 7 – 17 ÷ 3 \(\displaystyle =\frac{18}{7}-\frac{17}{3}\), a negative number, not 38.