Ten years ago, the ages of the members of a joint family of eight people added up to 231 years. Three years later, one member died at the age of 60 years and a child was born during the same year. After another three years, one more member died, again at 60, and a child was born during the same year. The current average age of this eight-member joint family is nearest to
Answer: C The total age of all the eight people in the family = 231 As per the information given in the question, the total age of all the people in the family = 231 + 3 × 8 – 60 + 0 = 195 Similarly the total age of the people in the family four years ago = 195 + 3 × 8 – 60 + 0 = 159. Therefore the current average age of all the people in the family => (159+32)/8 = 24 years
Q. No. 38:
Five times P's income added to Q's income is more than Rs 51. Three times P's income is more than Rs 21 from Q's income. Find out the possible range of values of p and q if they represent P's and Q's income respectively.
Answer: C 5p+q >51..............(i) 3p-q = 21...............(ii) From (ii), p = (21+q)/3 => (21+q)/3 >9 => b>6 Combining eq(1) and b>6 we get => a>9 and b>6
Q. No. 39:
Average age of the boys in the class of 50 is 13. The weights of each is directly proportional to the height and the height is also found to be in direct proportional to the age. A boy of age 11 is 165 cm tall, with weight being 33 kg. Find the average weight of the class.
Answer: B Average age = 13, Number of students = 50 W= X1H and H = X2A => W = X1X2A For A=11, H=165 and W=33 X1X2= 3 => W = 3A W is direct proportional to age , the average should also be in direct proportional Wavg =X1X2Aavg = 3*13 =39 kg
Q. No. 40:
A firm produces units of tyres (x>0) at a total cost of Rs (100x - 3x2 +x3/3). Then, the average cost per tyre is minimized for x, is equal to
Answer: D Total cost of tyres = (100x - 3x2 +x3/3) Average cost of one tyre = 100 -3x + x2/3 Now, this is quadratic expression which at minimum value at x = -b/2a = 45.
Q. No. 41:
A box contains 85 nuts each of 100g and 94 bolts each of 150g. If the entire box with its contents weighs 42.5 kg, then what is the weight of the empty box ?