A bicycle wheel makes 5000 revolutions in moving 11 km. The diameter of the wheel (in cm) is

• 35

• 55

• 65

• 70

At each corner of the triangular filed of sides 26 m, 28 m and 30 m, a cow is tethered by a rope of length 7m. The area (in m²) ungrazed by the cows is

• 336

• 259

• 154

• 77

A shopkeeper allows 23% commission on his advertised price and still makes a profit of 10%. If he gains ₹ 56 on one item, his advertised price of the item (in ₹) is

• 820

• 780

• 790

• 800

The single discount equal to three consecutive discount of 10%,  12% and 5% is

• 26.27%

• 24.76%

• 9%

• 11%

If  x  :  y  = 5 : 6  then (3x² - 2y²) : (y² - x²) is

• 7 : 6

• 11 : 3

• 3 : 11

• 6 : 7

An alloy contains copper, zinc and nickel in the ratio of 5 : 3  : 2. The quantity of nickel in kilogram that must be added to 100 kg of this alloy to have the new ratio 5 : 3 : 3 is

• 8

• 10

• 12

• 15

The ratio of the ages of Ram and Rahim 10 yr ago was 1 : 3. The ratio of their ages 5 yr hence will be 2 : 3. Then, the ratio of their present ages is

• 1 : 2

• 3 : 5

• 3 : 4

• 2 : 5

The incomes of A, B and C are in the ratio 7 : 9 : 12 and their spending are in the ratio 8 : 9 : 15. If A saves 1/4 of his income, then the saving of A, B and C are in the ratio of 

• 69 : 56 : 48

• 47 : 74 : 99

• 37 : 72 : 49

• 56 : 99 : 69

139.

Out of 4 numbers, whose average is 60, the first one is one-fourth of the sum of the last three. The first number is

• 15

• 45

• 48

• 60

The average of 25 observations is 13. It was later found that an observation 73 was wrongly entered as 48. The new average is

• 12.6

• 14

• 15

• 13.8