Question : Directions: By interchanging the given two signs and numbers which of the following equations will be not correct?
+ and –, 3 and 5
Option 1: 5 × 4 + 3 – 6 ÷ 2 = 10
Option 2: 7 × 4 ÷ 2 – 5 + 3 = 12
Option 3: 5 × 4 – 3 + 4 ÷ 2 = 15
Option 4: 5 – 3 + 8 × 4 ÷ 2 = 10
Correct Answer: 5 – 3 + 8 × 4 ÷ 2 = 10
Solution :
Given:
+ and –, 3 and 5
Replace the given symbols and numbers in the options one by one with the original symbols and numbers in the given equation.
First option:
5 × 4 + 3 – 6 ÷ 2 = 10
3 × 4 – 5 + 6 ÷ 2
= 3 × 4 – 5 + 3
= 12 – 5 + 3
= 12 – 2
= 10
Second option:
7 × 4 ÷ 2 – 5 + 3 = 12
7 × 4 ÷ 2 + 3 – 5
= 7 × 2 + 3 – 5
= 14 + 3 – 5
= 14 – 2
= 12 = R.H.S
Third option:
5 × 4 – 3 + 4 ÷ 2 = 15
3 × 4 + 5 – 4 ÷ 2
= 3 × 4 + 5 – 2
= 12 + 5 – 2
= 12 + 3
= 15
Fourth option:
5 – 3 + 8 × 4 ÷ 2 = 10
3 + 5 – 8 × 4 ÷ 2
= 3 + 5 – 8 × 2
= 3 + 5 – 16
= 3 – 11
= – 8 ≠ 10
Here, only the fourth option does not satisfy the R.H.S. of the given equation. Hence, the fourth option is correct.
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