If ÃÂÃÂ ÃÂÃÂ ÃÂÃÂ then the value of k is -
(A) 12
(B) 15
(C) 16
(D) 18
Solution:
115.
If a : b = 2 : 3 and b : c = 4 : 5, then (a + b) : (b + c) is equal to-
(A) 6 : 8
(B) 8 : 6
(C) 20 : 27
(D) 27 : 20
Solution:
116.
If A : B = 7 : 9 and B : C = 5 : 4, then A : B : C is -
(A) 7 : 45 : 36
(B) 28 :36 : 35
(C) 35 : 45 : 36
(D) None of these
Solution:
117.
The ratio of the monthly incomes of X and Y is 5 : 4 and that of their monthly expenditures is 9 : 7. If the income of Y is equal to the expenditure of X, then what is the ratio of the saving of X and Y?
If A : B = 7 : 9 and B : C = 3 : 5 then A : B : C is equal to = ?
(A) 7 : 9 : 5
(B) 21 : 35 : 45
(C) 7 : 9 : 15
(D) 7 : 3 : 15
Solution:
Given, A : B = 7 : 9 B : C = 3 : 5 Equal the value of B in both equation B : C = 3 : 5 (multiply with 3) i.e. B : C = 9 : 15 ∴ A : B : C = 7 : 9 : 15
119.
In a school, of the number of students are girls and the rest are boys. of the number of boys are below 14 years of age, and of the number of girls are 14 years or above 14 years of age. If the number of students below 14 years of age is 1120, then the total number of students in the school is:
(A) 1900
(B) 1820
(C) 1290
(D) 1920
Solution:
Let total student = 12 unit B : G 7 : 5 B → (14 year less) B = 4 (14 year less) G → G = 3 (14 year less) Total student less than 14 year = 4 + 3 = 7 7 → 1120 1 → 160 12 → 1920 total student
120.
The ratio of incomes of two persons is 5 : 3 and that of their expenditures is 9 : 5. If they save Rs. 2600 and Rs.1800 respectively, their incomes are.
(A) Rs. 9000, Rs. 5400
(B) Rs. 10000, Rs. 6000
(C) Rs. 6000, Rs. 3600
(D) Rs. 8000, Rs. 4800
Solution:
Let the incomes of the two persons be 5x and 3x and their expenditures be 9y and 5y respectively. Then, = 5x - 9y = 2600.....(i) = 3x - 5y = 1800.....(ii) Multiplying (i) by 3 and (ii) by 5, we get: = 15x - 27y = 7800.....(iii) = 15x - 25y = 9000.....(iv) Subtracting (iii) from (iv), we get : 2y = 1200 or y = 600 Putting y = 600 in (i), we get : 5x = 8000 or x = 1600. ∴ Their incomes are Rs. (5 × 1600) and Rs. (3 × 1600)i.e. Rs. 8000 and Rs. 4800 respectively