Search Previous Year Questions

Follow BODMAS rule to solve this question, as per the order given below,

Step - 1 - Parts of an equation enclosed in the ‘BRACKETS’ must be solved first

Step - 2 - Any mathematical ‘OF’ or ‘EXPONEMTS’ must be solved next

Step - 3 - Next the part of the equation that contains ‘DIVISION; and ‘MULTIPLICATION’ are calculated

Step - 4 - Last but not least, the parts of the equation that contains ‘ADDITION’ and ‘SUBTRACTION’ should be calculated

Now, the given expression:

⇒ (14)² + (19)² – (11)² + ? = (21)²

⇒ 196 + 361 – 121 + ? = 441

⇒ 557 – 121 + ? = 441

⇒ 436 + ? = 441

⇒ ? = 441 – 436

⇒ ? = 5

Given expression:

⇒ 74% of 2650 + 30% of 320 = ?

⇒ $\frac{{74}}{{100}}; \times ;2650; + ;\frac{{30}}{{100}}; \times ;320; = ;?$

⇒ ? = 1961 + 96

⇒ ? = 2057

Calculation:

20% of 25% of 40% of 2500

⇒ (20/100) of (25/100) of (40/100) of 2500

⇒ (1/5) × (1/4) × (2/5) × 2500 

⇒ (2/100) × 2500 

⇒ 50

∴ The correct answer is option 3

[(84)² ÷ 28 × 12] ÷ 24 = 7 × ?

⇒ [7056 ÷ 28 × 12] ÷ 24 = 7 × ?

⇒ [252 × 12] ÷ 24 = 7 × ?

⇒ 3024 ÷ 24 = 7 × ?

⇒ 126 = 7 × ?

∴ ? = 18

Given expression is,

⇒ {(7999 + 2001) ÷ 4} × 0.05 = (5)^?

⇒ (10000 ÷ 4) × 0.05 = (5)^?

⇒ (2500 × 0.05) = (5)^?

⇒ 125 = (5)^?

⇒ 5³ = 5^?

⇒ ? = 3

Given expression is,

⇒ 27% of 500 + 81% of 600 = ?% of 6900

$\Rightarrow \frac{{27}}{{100}} \times 500 + \frac{{81}}{{100}} \times 600 = \frac{?}{{100}} \times 6900$

⇒ 135 + 486 = 69 × ?

⇒ 621 = 69 × ?

⇒ ? = 9

Follow BODMAS to solve this question, as per the order given below,

Step-1: Parts of an equation enclosed in ‘Brackets’ must be solved first,

Step-2: Any mathematical ‘Of’ or ‘Exponent’ must be solved next,

Step-3: Next, the parts of the equation that contains ‘Division’ and ‘Multiplication’ are calculated,

Step-4: Last but not the least, the parts of the equation that contains ‘Addition’ and Subtraction’ should be calculated.

Given expression,​

⇒ 4.25% of 740 – ?% of 680 = 7.65

$\begin{array}{l} \Rightarrow \frac{{4.25}}{{100}}; \times ;740 - ;\frac{?}{{100}}; \times ;680; = ;7.65\ \Rightarrow {\rm{;}}31.45; - ;\frac{?}{{100}}; \times ;680; = ;7.65\ \Rightarrow \frac{?}{{100}}; \times ;680; = ;31.45; - ;7.65\ \Rightarrow ?; = ;23.8; \times ;\frac{{100}}{{680}}; \end{array}$

⇒ ? = 3.5

Given expression:

⇒ ? % of 560 – 25% of 340 – 12 × 9 = 3

$\begin{array}{l} \Rightarrow {\rm{;}}\frac{x}{{100}}; \times ;560 - ;\frac{{25}}{{100}}; \times ;340; - 12; \times ;9; = ;3\ \Rightarrow {\rm{;}}\frac{x}{{100}}; \times ;560 - ;85; - 108; = ;3\ \Rightarrow {\rm{;}}\frac{x}{{100}}; \times ;560; = ;3; + ;108; + ;85\ \Rightarrow {\rm{;}}\frac{x}{{100}}; \times ;560; = ;196\ \Rightarrow x; = ;196; \times ;\frac{{100}}{{560}}; \end{array}$

⇒ x = 35

Shortcut Trick

Difference between downstream speed and upstream speed is 2 × speed of stream (v).

2v = 8 ⇒ v = 4 km/hr.

Still water speed (u) = 10 km/hr. Upstream speed = 10 − 4 = 6 km/hr. Downstream speed = 10 + 4 = 14 km/hr.

Total time = (54 ÷ 6) + (42 ÷ 14) = 9 + 3 = 12 hr.

∴ The correct answer is 12 hr.

Alternate Method

Given:

Speed of boat in still water (u) = 10 km/hr.

Downstream Speed (D) − Upstream Speed (U) = 8 km/hr.

Formula Used:

D = u + v and U = u − v, where v is the speed of stream.

Time = Distance ÷ Speed.

Calculations:

⇒ (u + v) − (u − v) = 8

⇒ 2v = 8 ⇒ v = 4 km/hr.

⇒ Upstream speed (U) = 10 − 4 = 6 km/hr.

⇒ Downstream speed (D) = 10 + 4 = 14 km/hr.

⇒ Time taken upstream = 54 ÷ 6 = 9 hr.

⇒ Time taken downstream = 42 ÷ 14 = 3 hr.

⇒ Total time = 9 + 3 = 12 hr.

∴ The correct answer is 12 hr.

Additional Information

Downstream and Upstream Speed

Downstream speed (D) = u + v and Upstream speed (U) = u − v. Note that u is always greater than v for the boat to move upstream.

Still Water Speed Calculation

Speed of boat in still water (u) = (D + U) ÷ 2. This is the arithmetic mean of downstream and upstream speeds.

Stream Speed Calculation

Speed of the stream (v) = (D − U) ÷ 2. It represents half the difference between downstream and upstream speeds.

Given:

Shop A = 22 visitors

Shop D = 30 visitors

Calculation:

Difference = Visitors(Shop D) − Visitors(Shop A) = 30 − 22 = 8

Hence, the correct answer is 8.