a. 3 : 13 : 7
b. 3 : 36 : 28
c. 27 : 16 : 28
d. 27 : 36 : 28
Answer: d. 27 : 36 : 28
Explanation:
B is common to both the ratios.
Values of b = 4 and 9 (That means they are not the same)
Make the values of 'b' same as follows -
Multiply 3:4 up and down with 9 as shown
∴
3 x 9
=
27
=
a
4 x 9
36
b
Multiply 9:7 up and down with 4 as shown
∴
9 x 4
=
36
=
b
7 x 4
28
c
Since, values of b are same = 36 a : b : c = 27 : 36 : 28
7. Ram saves Rs 3395/- from his salary. He needs to pay this money as milk bill, electricity bill and mobile phone bill in the ratio 42 : 32 : 23. Find the money to be paid for each bill.
a. Rs 1245/-, Rs 1150/- and Rs 1000/-
b. Rs 1470/-, Rs 1120/- and Rs 805/-
c. Rs 1550/-, Rs 1235/- and Rs 610/ -
d. Rs 1764/-, Rs 1022/- and Rs 529/-
Answer: b. Rs 1470/-, Rs 1120/- and Rs 805/-
Explanation:
Common factor helps in finding actual values easily
So, take 'A' as common factor.
∴ 3 numbers will now be 42A, 32A and 23A
∴ 42A + 32A + 23 A = 3395
∴ 97A = 3395
∴ A = 35
3 parts of 3395 are 42A = 42 x 35 = 1470;
32A = 32 x 35 = 1120
23A = 23 x 35 = 805
These are the amounts to be paid.
8. Three numbers add up to 285 such that the ratio between first two numbers is 3:7 while the ratio between second and third number is 6:5. Find the value of the second number.
a. 124
b. 126
c. 135
d. 150
Answer: b. 126
Explanation:
1st number : 2nd number = 3:7 =
3
7
2nd number : 3rd number = 6:5 =
6
5
Values of 2nd number = 7 and 6 (They are not the same)
Make the values of 2nd number same as follows -
Multiply 3:7 up and down with 6 as shown
∴
3 x 6
=
18
=
1st Number
7 x 6
42
2nd Number
Multiply 6:5 up and down with 7 as shown
∴
6 x 7
=
42
=
2nd Number
5 x 7
35
3rd Number
Values of 2nd number are now same = 42
1st number : 2nd number = 18 : 42
2nd number : 3rd number = 42 : 35
1st number : 2nd number : 3rd number = 18 : 42 : 35
Common factor helps in finding actual values easily
So, take 'A' as common factor.
So now the 3 numbers are 18A, 42A and 35A
∴ 18A + 42A + 35A = 285
∴ A = 3 2nd number = 42A = 42 x 3 = 126
9. Ram and Shyam were carrying some money such that their money was in the ratio 3:8. A friend gives each of them Rs 5/- and their money is now in the ratio 2:5. Which is the smaller money of the two?
a. 45
b. 64
c. 105
d. 120
Answer: a. 45
Explanation:
Ratio of original money numbers = 3:8
Common factor helps in finding actual values easily
So, take 'M' as common factor.
∴ Original numbers will be 3M and 8M
Adding 5 to them, we get (3M + 5) and (8M+5)
∴
3M+5
=
2
-----------------> (Ratio of new numbers is 2:5)
8M+5
5
∴ 15M + 25 = 16M + 10
∴ M = 15 Smaller money value is 3M = 3 x 15 = 45
10. In a pitcher carries a mixture of alcohol and water for a party in the ratio 4:3 but the pitcher is still empty. If 2 bottles of water 3 litres and 2 litres respectively are emptied in the pitcher, the ratio changes to 4:5. How much alcohol does the mix contain?
