Breakup G Strategy | Concepts of Time Speed Distance | Easy
Rita and Sneha can row a boat at 5 km/h and 6 km/h in still water, respectively. In a river flowing with a constant velocity, Sneha takes 48 minutes more to row 14 km upstream than to row the same distance downstream. If Rita starts from a certain location in the river, and returns downstream to the same location, taking a total of 100 minutes, then the total distance, in km, Rita will cover is ______
Answer & Explanation
Concept of upstream and Downstream:
Sneha’s speed = 6 km/h, let river speed = x km/h
Time difference: 14/(6-x) – 14/(6+x) = 0.8 , x = 1 km/h
Rita’s effective speed
Upstream = 5 – 1 = 4 km/h
Downstream = 5 + 1 = 6 km/h
Time to go and return = 100 min = 5/3 h
d/4 + d/6 = 5/3 , d = 4 km
Total distance:
Total distance = 4 + 4 = 8 km
Answer: 8 km
Breakup G Strategy | Mixtures + Equations | Moderate
A mixture of coffee and cocoa, 16% of which is coffee, costs Rs 240 per kg. Another mixture of coffee and cocoa, of which 36% is coffee, costs Rs 320 per kg. If a new mixture of coffee and cocoa costs Rs 376 per kg, then the quantity, in kg, of coffee in 10 kg of this new mixture is
A) 6
B) 2.5
C) 5
D) 4
Answer & Explanation
Correct Answer (c) 5 kg
Let the price of coffee be C and that of cocoa be K (per kg).
From the first mixture (16% coffee, price 240):
0.16C + 0.84K = 240
From the second mixture (36% coffee, price 320):
0.36C + 0.64K = 320
Multiply both equations by 100:
16C + 84K = 24000
36C + 64K = 32000
Solve these two:
From the pair, you get K = 176 and then C = 576.
Now for the new mixture with price 376 and coffee fraction x:
576x + 176(1 − x) = 376→576x + 176 − 176x = 376 → 400x = 200 → x = 0.5
So the new mixture has 50% coffee.
Therefore, in 10 kg of the new mixture, coffee = 0.5 × 10 = 5 kg.
Shortcut method:
Coffee % goes from 16% → 36%, Price goes from 240 → 320
So an increase of 20% coffee increases price by 80 ⇒ Each 1% coffee increases price by 4.
Now compare old price to new price → Price of new mixture = 376 → Difference from cheaper mixture = 376 − 240 = 136
So increase in coffee % = 136 ÷ 4 = 34%
Hence coffee % in new mixture = 16% + 34% = 50%
So in 10 kg, coffee = 50% of 10 = 5 kg
Breakup G strategy | Averages + Linear Equation | Easy
The average number of copies of a book sold per day by a shopkeeper is 60 in the initial seven days and 63 in the initial eight days, after the book launch. On the ninth day, she sells 11 copies less than the eighth day, and the average number of copies sold per day from second day to ninth day becomes 66. The number of copies sold on the first day of the book launch is ____
Answer & Explanation
Correct Answer: 49 copies
First 7 days avg = 60 ⇒ total = 7 × 60 = 420
First 8 days avg = 63 ⇒ total = 8 × 63 = 504
8th day sales = 504 − 420 = 84
9th day sales = 84 − 11 = 73
Avg from 2nd to 9th day = 66 ⇒ total (2nd–9th) = 8 × 66 = 528
Total (1st–9th) = 504 + 73 = 577
1st day sales = 577 − 528 = 49
LCM G Strategy | Time & Work | Moderate
Ankita is twice as efficient as Bipin, while Bipin is twice as efficient as Chandan. All three of them start together on a job, and Bipin leaves the job after 20 days. If the job got completed in 60 days, the number of days needed by Chandan to complete the job alone is
Answer & Explanation
Correct Answer 340
Let Chandan’s efficiency be 1 unit/day.
Then Bipin’s efficiency = 2 units/day and Ankita’s efficiency = 4 units/day.
For the first 20 days, all three work together, so work done = (4 + 2 + 1) × 20 = 140 units.
For the remaining 40 days, only Ankita and Chandan work, so work done = (4 + 1) × 40 = 200 units.
Total work = 140 + 200 = 340 units.
Since Chandan alone does 1 unit of work per day, he would complete the job in 340 days.
Correct Answer D) 14
Given: CP = 1650, MP = 2200
Condition: profit % = discount %
| Discount % | SP = MP × (1 − d) | Profit (SP − 1650) | Profit % | Match? |
| A. 12% | 2200 × 0.88 = 1936 | 286 | ≈ 17% | ❌ |
| B. 18% | 2200 × 0.82 = 1804 | 154 | ≈ 9% | ❌ |
| C. 16% | 2200 × 0.84 = 1848 | 198 | ≈ 12% | ❌ |
| D. 14% | 2200 × 0.86 = 1892 | 242 | ≈ 14.7% | ✅ |
