The mean salary of ABD Ltd. was Rs 1500, and the standard deviation was Rs 400. A year later each employee got a Rs 100 raise. After another year each employee's salary (including the above mentioned raise) was increased by 20%. The standard deviation of the current salary is:
Answer: B When a constant value is added to all the numbers of a set then there is no effect on standard deviation. But if we multiply all the terms by any constant factor standard deviation of the resulting numbers also gets gets multiplied by that factor. Hence, on increasing the salary by 20% Standard deviation will also increases by 20% Hence, new standard deviation will be = 1.2 * 400 = 480.
Q. No. 8:
If the price of sugar is raised by 25%, by how much should a household reduce its consumption of sugar so as not to increase expenditure on sugar?
Answer: A Expenditure = Price × Cosumption E = P × C New price = 1.25P Let C’ be new consumption, E is constant E = 1.25P × C’ P × C = 1.25 P × C’ => C' = 1/1.25 = 0.8 = 80% Reduction in consumption is 20%
Q. No. 9:
The number of bacteria on the bread be 3,11,250. The ratio of number of male and female is 1075:100. There are 24% eating the bread among males and 8% among females. What is the total number of bacteria on bread with eating it?Approximately what % of bacteria on the bread are not eating it?
Answer: C We see that the ratio is 1075:1000, when converted to percentage terms, is approximately 52% : 48%. Thus, we can calculate the number of bacteria eating the bread => 24*52/100 + 8*48/100 = 16.3% Now,as 100- 16.3 = 83.7 %. Number of bacteria who really eats the bread => 16.3/100 * 311250 = 50,700
Q. No. 10:
The rate of increase in prices in a particular village is 1000% per annum compoundedly. What will be the cost in 2001 of a product which costs 5 units of currency in 1999?
Answer: C The rate of inflation =1000% => The cost of the unit will increase at 1000% The cost of the unit will increase at the rate of 1000+100 = 1100% rate => The cost of 5 units after 2 years will be 5 * 1100/100 * 1100/100 = 55*11= 605 units
Q. No. 11:
A school needs funds for a new building. 80% of the people that the school approached for funds gave an average contribution of Rs 600 each, there by making upto 75% of the total amount needed, what should be the average contribution from the remaining people, the school has approached for donations?
Answer: B Let the total number of people the school has asked be 100. Amount collected from 80% of people = 80*600 = Rs 48,000 This is 75% of the total contribution Remaining 25% of the total contribution = Ra 16,000 16,000 is to be donated by 20% i.e 20 people Average per person = 16,000/20 = Rs 800
Q. No. 12:
Mr. Haque's otal annual gross salary, which was Rs 10 lakhs per year in 2007, has been reduced by 10% in 2008. In 2007 his family expenditure for food items was 40% of the total annual gross salary. The prices of average food items have increased by 5% between 2007 and 2008. Assuming that the family consumed the same amount of food in 2008, the percentage expenditure on food items, calculated on total annual gross salary in 2008, is approximately
Answer: C Mr. Haque's salary in 2008 = 9,00,000 rupees. Expenditure on food in 2007 = 4,00,000 rupees. Expenditure on food in 2008 = 4,00,000 + 4,00,000 * 5/100 = 4,20,000 rupees. percentage expenditure on food items in 2008 = (4,20,000/9,00,000) * 100 => 47%(approximately).