Quantitative Aptitude - MCQ Practice Questions

Let CP = 100. MP = 160. After 25% discount, SP = 160 × 0.75 = 120. Profit = 120 - 100 = 20. Profit% = 20%.

x% of 400 = 20% of 500. (x/100) × 400 = 0.2 × 500. 4x = 100. x = 25.

B takes 30 days, so B's rate = $\frac{1}{30}$. A works twice as fast, so A's rate = $\frac{2}{30}$ = $\frac{1}{15}$. Combined rate = $\frac{1}{30}$ + $\frac{1}{15}$ = $\frac{1}{30}$ + $\frac{2}{30}$ = $\frac{3}{30}$ = $\frac{1}{10}$. Time taken = 10 days.

35% of x = 105. x = $\frac{105}{0}$.35 = 300. 65% of 300 = 0.65 × 300 = 195.

Rate of pipe 1 = $\frac{1}{15}$, Rate of pipe 2 = $\frac{1}{20}$. Combined rate = $\frac{1}{15}$ + $\frac{1}{20}$ = $\frac{4}{60}$ + $\frac{3}{60}$ = $\frac{7}{60}$. Time = $\frac{60}{7}$ ≈ 8.57 minutes.

Speed = $\frac{200}{5}$ = 40 km/h. Distance in 8 hours = 40 × 8 = 320 km.

To find the final price after two successive percentage changes, apply each change sequentially to the original price.

Step 1: Calculate price after 25% increase in Year 1

Initial price = Rs. 1000

A 25% increase means the new price is 125% of the original:

Step 2: Calculate price after 20% decrease in Year 2

The price decreases by 20% from Rs. 1250, so the new price is 80% of the previous price:

Alternative approach (combined multiplier):

Apply both changes as a single operation:

Note that the multipliers $1.25\times 0.80=1.00$, meaning the two percentage changes exactly cancel out.

Answer: Rs. 1000 (Option C)

Boat speed = (Downstream + Upstream) / 2 = (20 + 12) / 2 = $\frac{32}{2}$ = 16 km/h.

B's rate = $\frac{1}{24}$. A is 50% more efficient, so A's rate = 1.5 × ($\frac{1}{24}$) = 1.$\frac{5}{24}$ = $\frac{1}{16}$. A takes 16 days.

If sum doubles in 5 years: 2P = P + SI, so SI = P. Rate = (SI × 100) / (P × T) = (P × 100) / (P × 5) = 20%. For sum to become 4 times: 4P = P + SI, so SI = 3P. Time = (SI × 100) / (P × R) = (3P × 100) / (P × 20) = 15 years.

CP = 700. For 20% profit, SP = 700 × 1.2 = 840. After 30% discount, SP = 0.7 × MP. So 840 = 0.7 × MP. MP = $\frac{840}{0}$.7 = 1200.

Profit % = [(140 × 85)/100 - 100] = [119 - 100] = 19%

Number = $\frac{180}{0}$.45 = 400. So 80% of 400 = 320

SI = (8000 × 12 × 1.5)/100 = 1440. Amount = 8000 + 1440 = Rs. 9440

Combined rate = $\frac{1}{24}$ + $\frac{1}{36}$ = (3+2)/72 = $\frac{5}{72}$. Time = $\frac{72}{5}$ = 14.4 minutes

Speed in m/s = 72 × $\frac{5}{18}$ = 20 m/s. Distance = 20 × 25 = 500 m

When a boat moves in a river, its effective speed changes based on the stream direction. We use the formulas: Downstream speed = boat speed + stream speed, and Upstream speed = boat speed − stream speed.

Step 1: Calculate Downstream Speed

Downstream means the boat moves with the stream (both speeds add):

Step 2: Calculate Upstream Speed

Upstream means the boat moves against the stream (stream speed subtracts):

Step 3: Find the Ratio

The ratio of downstream to upstream speed is:

This simplifies to $3:2$.

**Answer: The ratio of downstream to upstream speed is $3:2$ (Option B)**

A = P(1.1)³ = 1.331P. Given A = 1331, so P = 1000

B's rate = $\frac{1}{12}$ - $\frac{1}{20}$ = (5-3)/60 = $\frac{2}{60}$ = $\frac{1}{30}$. B takes 30 days

After 10% discount: 800 × 0.9 = 720. After 15% discount: 720 × 0.85 = 612