# Aptitude [TCS Placement]: Sample Questions 154 - 156 of 174

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## Question 154

Aptitude

### Question

MCQ▾

Two pipes can fill a tank in 10 hrs and 12 hrs respectively while a third pipe empties the full tank in 20 hrs. If all the three pipes operate together, in how much time the tank will be filled?

Choice (4)

a.

6 hrs.

b.

7.5 hrs.

c.

8.5 hrs.

d.

8 hrs.

b.

### Explanation

• Two pipes can fill a tank in 10 hrs and 12 hrs respectively.
• A third pipe empties the full tank in 20 hrs.
• Net part filled in 1 hour

• So, tank will be full in hrs = 7 hrs 30 minutes

## Question 155

Aptitude
Edit

### Write in Short

If we roll two dice at a time then what is the probability that the no. obtained from both of them makes a sum of either 3 or 4?

### Explanation

• If we roll two dice simultaneously then there are total 36 possible cases.
• Sum of multiple of 3 or 4 = { (1,2) , (1,3) , (1,5) , (2,1) , (2,2) , (2,4) , (2,6) , (3,1) , (3,3) , (3,5) , (3,6) , (4,2) , (4,4) , (4,5) , (5,1) , (5,3) , (5,4) , (6,2) , (6,3) , (6,6) } = 20
• We are asked to find the probability that the number obtained from both dice makes a sum of either 3 or 4

## Question 156

Aptitude

### Write in Short

The ratio of incomes of C and D is . the ratio of their expenditures is . Find the ratio of their savings if the savings of C is one fourths of his income?

### Explanation

• Income of C: 3x
• Income of D: 4x
• Expenditure of C: 4y
• Expenditure of D: 5y
• Savings of C: 3x - 4y
• Savings of D: 4x - 5y
• We are asked to find the ratio of savings if savings of C is one fourth of his income.
• In equation,

• Now savings of C: 3x - 4y

• Now savings of D: 4x - 5y

• Ratio of savings of C and D

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