Question

Which two signs should be interchanged to make the following equation mathematically correct? 49 + 7 × 10 ÷ 6 - 3 = 73

• A. + and -
• B. x and +
• C. - and x
• D. + and ÷

Answer 1

Answer:

D. + and ÷

Check the given expression:

$49 + 7 \times 10 \div 6 - 3$
Try interchanging × and ÷

New expression:
$49 + 7 \div 10 \times 6 - 3$

Apply BODMAS:

$7 \div 10 \times 6 = \frac{7}{10} \times 6 = 4.2$

$49 + 4.2 - 3 = 50.2$

Not correct.

Try interchanging + and ×

$49 \times 7 + 10 \div 6 - 3$
$49 \times 7 = 343,\quad 10 \div 6 \approx 1.67$
$343 + 1.67 - 3 \approx 341.67$

Not correct.

Try interchanging + and ÷

$49 \div 7 \times 10 + 6 - 3$

$49 \div 7 = 7,\quad 7 \times 10 = 70$

$70 + 6 - 3 = 73$

Final Answer: ‘+’ and ‘÷’