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41. Number of students in institutes A and B were in the ratio of 7 : 15 respectively in 2012. In 2013, the number of students in institute A increased by 25% and number of students in institutes B increased by 26%, then what was the respective ratio between number of students in institutes A and B?

Discuss
Solution:
Ratio of students in 2012 in institutes A and B = 7 : 15
Let number of students in institute A in 2012 = 700
And Number of students in institutes B in 2012 = 1500
25% increase in the number of students in 2013
Now, number of students in Institute A = 700 + 25% of 700 = 875
Number of students in B in 2013 as 26% students increased in B
= 1500 + 26% of 1500 = 1890
Current Ratio of the students,
=8751890=25:54
42. A and B together have Rs. 1210. If 415 of A's amount is equal to 25 of B's amount, how much amount does B have?

Discuss
Solution:
415A=25BA=(25×154)BA=32BAB=32A:B=3:2.B'sshare=Rs.(1210×25)=Rs.484
43. Two numbers are respectively 20% and 50% more than a third number. The ratio of the two numbers is:

Discuss
Solution:
LetthethirdnumberbexThen,firstnumber=120%ofx=120x100=6x5Secondnumber=150%ofx=150x100=3x2Ratiooffirsttwonumbers=6x5:3x2=12x:15x=4:5
44. A sum of money is to be distributed among A, B, C, D in the proportion of 5 : 2 : 4 : 3. If C gets Rs. 1000 more than D, what is B's share?

Discuss
Solution:
Let the shares of A, B, C and D be Rs. 5x, Rs. 2x, Rs. 4x and Rs. 3x respectively
Then, 4x - 3x = 1000
⇒ x = 1000
∴ B's share = Rs. 2x = Rs. (2 x 1000) = Rs. 2000
45. Seats for Mathematics, Physics and Biology in a school are in the ratio 5 : 7 : 8. There is a proposal to increase these seats by 40%, 50% and 75% respectively. What will be the ratio of increased seats?

Discuss
Solution:
Originally, let the number of seats for Mathematics, Physics and Biology be 5x, 7x and 8x respectively
Number of increased seats are (140% of 5x), (150% of 7x) and (175% of 8x)
  =(140100×5x),     (150100×7x)   and (175100×8x)
=7x,21x2 and 14xThe required ratio=7x:21x2:14x=14x:21x:28x=2:3:4
46. In a mixture 60 litres, the ratio of milk and water 2 : 1. If this ratio is to be 1 : 2, then the quanity of water to be further added is:

Discuss
Solution:
Quantity of milk
=(60×23)litres=40litres
Quantity of water in it = (60 - 40) litres = 20 litres
New ratio = 1 : 2
Let quantity of water to be added further be x litres
Then,milk : water=4020+xNow,4020+x=1220+x=80x=60Quantityofwatertobeadded = 60litres.
47. The ratio of the number of boys and girls in a college is 7 : 8. If the percentage increase in the number of boys and girls be 20% and 10% respectively, what will be the new ratio?

Discuss
Solution:
Originally, let the number of boys and girls in the college be 7x and 8x respectively
Their increased number is (120% of 7x) and (110% of 8x)
(120100×7x)and(110100×8x)42x5and44x5Therequiredration=42x5:44x5=21:22
48. Salaries of Ravi and Sumit are in the ratio 2 : 3. If the salary of each is increased by Rs. 4000, the new ratio becomes 40 : 57. What is Sumit's salary?

Discuss
Solution:
Let the original salaries of Ravi and Sumit be Rs. 2x and Rs. 3x respectively
Then,2x+40003x+4000=4057
⇒ 57(2x + 4000) = 40(3x + 4000)
⇒ 6x = 68,000
⇒ 3x = 34,000
Sumit's present salary
= (3x + 4000)
= Rs. (34000 + 4000)
= Rs. 38,000
49. If 0.75 : x :: 5 : 8, then x is equal to:

Discuss
Solution:
x×5=0.75×8x=65x=1.2
50. The sum of three numbers is 98. If the ratio of the first to second is 2 :3 and that of the second to the third is 5 : 8, then the second number is:

Discuss
Solution:
Let the three parts be A, B, C. Then,
A : B = 2 : 3 and B : C = 5 : 8
=(5×35):(8×35)=3:245A:B:C=2:3:245=10:15:24B=98×1549=30