## Mathematical operation and symbol notation

#### Mathematical operation and symbol notation

Direction: If the given interchanges are made in signs and numbers, which one of the four equations would be correct?

1. Given interchanges signs 'x' and '÷'; numbers '4' and '9'
1. 94 x 7 ÷ 47 = 324
2. 94 x 7 ÷ 97 = 329
3. 49 x 7 ÷ 49 = 7
4. 47 x 9 ÷ 94 = 18

1. (a) 49 ÷ 7 x 97 ≠ 324
(b) 49 ÷ 7 x 47 = 329
(c) 94 ÷ 7 x 94 ≠ 7
(d) 97 ÷ 4 x 49 ≠ 18

##### Correct Option: B

(a) 49 ÷ 7 x 97 ≠ 324
(b) 49 ÷ 7 x 47 = 329
(c) 94 ÷ 7 x 94 ≠ 7
(d) 97 ÷ 4 x 49 ≠ 18

1. Select the correct combination of mathematical signs to replace * signs and to balance the following equation
8 * 8 * 1 * 7 = 8
1. x ÷ +
2. + ÷ x
3. ÷ x +
4. + x ÷

1. From option (c),
8 * 8 * 1 * 7 = 8
⇒ 8 ÷ 8 x 1 + 7 = 8
∴ 8 = 8

##### Correct Option: C

From option (c),
8 * 8 * 1 * 7 = 8
⇒ 8 ÷ 8 x 1 + 7 = 8
∴ 8 = 8

1. If '+' denotes ÷ , '-' denotes x, 'x' denotes - and '÷' denotes +, then
35 + 7 - 5 ÷ 5 x 6 = ?
1. 36
2. 24
3. 20
4. 14

1. According to the question,
35 ÷ 7 x 5 + 5 - 6 = ?
⇒ 5 x 5 + 5 - 6 = ?
⇒ 25 + 5 - 6 = ?
⇒ 30 - 6 = 24

##### Correct Option: B

According to the question,
35 ÷ 7 x 5 + 5 - 6 = ?
⇒ 5 x 5 + 5 - 6 = ?
⇒ 25 + 5 - 6 = ?
⇒ 30 - 6 = 24

Direction: In each of the following questions, all the equations except one have been solved according to a certain rule. You are required to solve the unsolved equation following the same rule and to choose the correct answer out of the given options.

1. 4 - 4 = 12, 6 - 6 = 30, 2 - 2 = 2, 8 - 8 = ?
1. 8
2. 38
3. 56
4. 16

1. As, 4 - 4 ⇒ 4 x 4 - 4 = 12
6 - 6 ⇒ 6 x 6 - 6 = 30
2 - 2 ⇒ 2 x 2 - 2 = 2

##### Correct Option: C

As, 4 - 4 ⇒ 4 x 4 - 4 = 12
6 - 6 ⇒ 6 x 6 - 6 = 30
2 - 2 ⇒ 2 x 2 - 2 = 2
Similarly, 8 - 8 ⇒ 8 x 8 - 8 = 56

1. 9 * 7 = 32, 13 * 7 = 120, 17 * 9 = 208, 19 * 11 = ?
1. 64
2. 160
3. 240
4. 210

1. As, 9 * 7 ⇒ (9 + 7) (9 - 7) = 16 x2 = 32
13 * 7 ⇒ (13 + 7) (13 - 7) = 20 x 6 = 120
17 * 9 ⇒ (17 + 9) (17 - 9) = 26 x 8 = 208

##### Correct Option: C

As, 9 * 7 ⇒ (9 + 7) (9 - 7) = 16 x2 = 32
13 * 7 ⇒ (13 + 7) (13 - 7) = 20 x 6 = 120
17 * 9 ⇒ (17 + 9) (17 - 9) = 26 x 8 = 208
Similarly, 19 * 11 ⇒ (19 + 11) (19 - 11) = 30 x 8 = 240
∴ ? = 240