Concept of “Simplification-02”

1. Q.  (16)² + (21)² – (13)² +? = (25)² [Ans. (4) 97]

(1) 67      (2) 32      (3) 81       (4) 97        (5) None of these

2. Q.  (?)² + (15)² – (33)² = 97 [Ans. (5) None of these (31)]

(1) 33      (2) 32         (3) 34         (4) 30          (5) None of these

3. Q. 15% of 524 – 2% of 985 +? = 20% of 423 [Ans. (3) 25.7]

(1) 25.9 (2) 27.7 (3) 25.7 (4) 24.9 (5) None of these

4. Q. 34928 – 2591 – 14986 =? [Ans. (3) 17351]

(1)  17546   (2) 17355   (3) 17351 (4) 17390 (5) None of these

5. Q. 23% of 1630 =? [Ans. (4) 374.9]

(1) 394.7 (2) 347.9 (3) 379.4 (4) 374.9 (5) None of these

Solution:

Detailed Explanation:  

1. Q.  (16)² + (21)² – (13)² +? = (25)² 

Sol.  (16)² – (13)² +? = (25)² - (21)²

Or, 29×3 +? = 46×4

Or, ? = 184 - 87

= 97 Ans.

2. Q.  (?)² + (15)² – (33)² = 97

Sol. (?)² = 97 + (33)² - (15)²

Or, (?)² = 97 + 48×18 [50×18 - 2×18]

Or, (?)² = 97 + 900 – 36  

Or, (?)² = 900 +61 = 961  

Or, ? = 31 Ans.

3. Q. 15% of 524 – 2% of 985 +? = 20% of 423

Sol. 15% of 524 – 2% of 985 +? = 20% of 423

Or, 78.6 – 19.7 +? = 84.6

Or, ? = 6 + 19.7 = 25.7 Ans.

4. Q. 34928 – 2591 – 14986 =?

Sol. ? = 34928 – 2591 – 14986

Or, ? = 35000 – 2600 – 15000 + [- 72 + 9 + 14]  [Since 34928 = 35000 – 72; - 2591 = -2600 + 9 and – 14986 = -15000 + 14]

Or, ? = 17400 – 49  

Or, ? = 17351  

5. Q. 23% of 1630 =?

Solution: 23% of 1630

= 25% of 1630 – 2% of 1630

= 407.5 – 32.60 [25% of 1630 = ¼ th of 1630 = ¼ th of 1600 + ¼ th of 30 and 2% of 1630 = 2 × 16.30 ]

= 374.9 Ans.