Which two signs and which two numbers should be interchanged to make the given equation correct?
12 × 5 + 7 ÷ 4 – 6 = 25
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → ‘÷’ and ‘–’, 4 and 12
Make both interchanges of an option, then work out the left side by BODMAS: division and multiplication first, then addition and subtraction from left to right.
Interchanging ÷ with – and 4 with 12 gives 4 × 5 + 7 – 12 ÷ 6
\(4\times5=20\)
\(12\div6=2\)
\(20+7-2=25\), which equals the right side
Why the other options are incorrect
Option (1) ‘×’ and ‘÷’, 7 and 6 — Incorrect. 12 ÷ 5 + 6 × 4 – 7 \(=2.4+24-7=\) 19.4, not 25.
Option (2) ‘×’ and ‘–’, 6 and 5 — Incorrect. 12 – 6 + 7 ÷ 4 × 5 \(=12-6+8.75=\) 14.75, not 25.
Option (4) ‘×’ and ‘+’, 12 and 4 — Incorrect. 4 + 5 × 7 ÷ 12 – 6 \(\displaystyle =4+\frac{35}{12}-6=\) \(\frac{11}{12}\), not 25.