**Reasoning and General Intelligence – Mathematical Operation**

Under this type of problem, usually mathematical symbol are converted into another form by either interchanging the symbol or using different symbol in place of usual symbol and then calculate the equation according to the given condition.

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**EXAMPLE 1.** If ‘+’ stands for division, ‘x’ stands for addition, ‘-’ stands for multiplication, and ‘÷’ stands for subtraction, then which of the following equation is correct?

(a) 36 × 6 + 7 ÷ 2 – 6 = 20

(b) 36 + 6 – 3 × 5 ÷ 3 = 24

(c) 36 + 6 + 3 × 5 – 3 = 45

(d) 36 – 6 + 3 × 5 ÷ 3 = 74

**Sol.** (d) 36 × 6 ÷ 3 + 5 – 3

36 × 2 + 5 – 3 = 74

**EXAMPLE 2**. If P denotes ‘+’, Q denotes ‘-‘ R denotes ‘×‘ and S denotes ‘÷’ then, which of the following statement is correct?

(a) 16 R 12 P 49 S 7 Q9 = 200

(b) 32S8R9 = 160Q 12R 12

(c) 8R8P8S8Q = 57

(d) 36R4S8Q7P4 = 10

**Sol.** (c) 8R8P8S8Q

= 8×8+88-8

= 8 × 8 + -8

= 64 +1- 8 = 57

**EXAMPLE 3. **Select correct combination of mathematical sign to replace ‘*’ sign to balance the equation.

9* 4* 22 *14

(a) x = – (b) × – =

(c) = – × (d) – × =

Sol. (b) 9* 4* 22 *14

9 × 4 – 22 = 14

**EXAMPLE 4**. Given interchange: sign ‘+’ and ‘-’ and numbers 5 and 8. Which of the following is correct?

(a) 82-35 + 55=2 (b) 82-35 + 55 = 102

(c) 85-38 + 85 = 132 (d) 52-35+55 = 72

Sol. (a) 52 + 38-88=2