Which two signs should be interchanged to make the given equation correct?
25 – 5 × 50 ÷ 10 + 35 = 155
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → × and –
Make the interchange of an option, then work out the left side by BODMAS: division and multiplication first, then addition and subtraction from left to right.
Interchanging × and – gives 25 × 5 – 50 ÷ 10 + 35
\(25\times5=125\)
\(50\div10=5\)
\(125-5+35=155\), which equals the right side
Why the other options are incorrect
Option (1) × and + — Incorrect. 25 – 5 + 50 ÷ 10 × 35 \(=20+175=\) 195, not 155.
Option (2) × and ÷ — Incorrect. 25 – 5 ÷ 50 × 10 + 35 \(=25-1+35=\) 59, not 155.
Option (4) + and – — Incorrect. 25 + 5 × 50 ÷ 10 – 35 \(=25+25-35=\) 15, not 155.