1.4 I FUNDAMENTALS OF BUSINESS MATHEMATICS AND STATISTICS
Arithmetic
Let the incomes be 4x and 3x (in `)
Now 4x 1000 33x 1000 2−− = or, x = 1000 (on reduction)
∴ Income of A = ` 4000, that of B = ` 3000.
Example 9 : The prime cost of an article was three times the value of material used. The cost of raw
materials was increased in the ratio 3 : 4 and the productive wage was increased in the ratio 4 : 5. Find the
present prime cost of an article, which could formerly be made for ` 180.
Prime cost = x + y, where x = productive wage, y = material used.
Now prime cost = 180 =3y or, y = 60, again x + y = 180, x = 180–y = 180–60 = 120
Present material cost = 4y 3 , present wage = 5x 4 ,
∴ Present prime cost =^4 × 3 60 5 120+ × 4 =80 150 230.+ =`
SELF EXAMINATION QUESTIONS :
- The ratio of the present age of a father to that of his son is 5 : 3. Ten years hence the ratio would be
3 : 2. Find their present ages. [Ans. 50,30] - The monthly salaries of two persons are in the ratio of 3 : 5. If each receives an increase of
20 in salary, the ratio is altered to 13 : 21. Find the respective salaries. [Ans.
240, ` 400] - What must be subtracted from each of the numbers 17, 25, 31, 47 so that the remainders may be in
proportion. [Ans. 3] - In a certain test, the number of successful candidates was three times than that of unsuccessful
candidates. If there had been 16 fewer candidates and if 6 more would have been unsuccessful, the
numbers would have been as 2 to 1. Find the number of candidates. [Ans. 136] - (i) Monthly incomes to two persons are in ratio of 4 : 5 and their monthly expenditures are in the
ratio of 7 : 9. If each saves50 a month, find their monthly incomes. [Ans.
400,500] (ii) Monthly incomes of Ram and Rahim are in the ratio 5 : 7 and their monthly expenditures are in the ratio 7 : 11. If each of them saves
60 per month. Find their monthly income.
[Ans. 200, ` 280]
hints^5 x 60 7 &etc.
7x 60 11
− =
(^) − (^)
- A certain product C is made or two ingredients A and B in the proportion of 2 : 5. The price of A is
three times that of B.
The overall cost of C is5.20 per tonne including labour charges of 80 paise per tonne. Find the cost A and B per tonne. [Ans.
8.40, ` 2.80] - The prime cost of an article was three times than the value of materials used. The cost of raw materials
increases in the ratio of 3 : 7 and productive wages as 4 : 9. Find the present prime cost of an article
which could formerly be made for18. [Ans.
41]