Quiz Discussion

In a laboratory experiment, a sample of air which is a mixture of oxygen and water vapour is taken. Water vapour, contains hydrogen and oxygen gases. If air contains a total of 70% oxygen (including that contained in the water vapour) by weight while water vapour contains 16.66% of oxygen by weight, how many kilograms of water vapour is present in 1 kilogram of air?

• 1]

  0.20

• 2]

  0.36

• 3]

  0.32

• 4]

  0.25

The actual area of a rectangle is 60 Cm2, but while measuring its length a student decreases it by 20% and the breadth increases by 25%. The percentage error in area, calculated by the student is :

• 1] 5%
• 2] 15%
• 3] 20%
• 4] No change

The cost of an article was Rs.75. The cost was first increased by 20% and later on it was reduced by 20%. The present cost of the article is:

• 1] Rs. 72
• 2] Rs. 60
• 3] Rs. 75
• 4] Rs. 76

30% of a number when subtracted from 91, gives the number itself. Find the number.

• 1] 60
• 2] 65
• 3] 75
• 4] 70
• 5] None of these

P is 6 times greater than Q then by what per cent is Q smaller than P?

• 1] 84%
• 2] 85.5%
• 3] 80%
• 4] 83.33%

In an institute, 60% of the students are boys and the rest are girls. Further 15% of the boys and 7.5% of the girls are getting a fee waiver. If the number of those getting a fee waiver is 90, find the total number of students getting 50% concessions if it is given that 50% of those not getting a fee waiver are eligible to get half fee concession?

• 1] 360
• 2] 280
• 3] 320
• 4] 330
• 5] 350

If a 36 inches long strip cloth shrinks to 33 inches after being washed, how many inches long will the same strip remain after washing if it were 48 inches long?

• 1] 47 inches
• 2] 44 inches
• 3] 45 inches
• 4] 46 inches

An alloy contains the copper and aluminum in the ratio of 7 : 4 While making the weapons from this alloy, 12% of the alloy got destroyed. If there is 12 kg of aluminum in the weapon, then weight of the alloy required is :

• 1] 14.4 kg
• 2] 37.5 kg
• 3] 40 kg
• 4] 48 kg

A college has raised 75% of the amount it needs for a new building by receiving an average donation of Rs. 600 from the people already solicited. The people already solicited represent 60% of the people, the college will ask for donations. If the college is to raise exactly the amount needed for the new building, what should be the average donation from the remaining people be solicited?

• 1] 300
• 2] 250
• 3] 400
• 4] 500

The cost of packaging of the mangoes is 40% the cost of fresh mangoes themselves. The cost of mangoes increased by 30% but the cost of packaging decreased by 50%, then the percentage change of the cost of packed mangoes, if the cost of packed mangoes is equal to the sum of the cost of fresh mangoes and cost of packaging :

• 1] 14.17%
• 2] 7.14%
• 3] 8.87%
• 4] 6.66%