# Aptitude - Ratio and Proportion - Discussion

Discussion Forum : Ratio and Proportion - General Questions (Q.No. 4)

4.

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?

Answer: Option

Explanation:

Originally, let the number of seats for Mathematics, Physics and Biology be 5*x*, 7*x* and 8*x* respectively.

Number of increased seats are (140% of 5*x*), (150% of 7*x*) and (175% of 8*x*).

140 | x 5x |
, | 150 | x 7x |
and | 175 | x 8x |
|||||||

100 | 100 | 100 |

7x, |
21x |
and 14x. |

2 |

The required ratio = 7x : |
21x |
: 14x |

2 |

14*x* : 21*x* : 28*x*

2 : 3 : 4.

Discussion:

74 comments Page 1 of 8.
Shwetha said:
1 decade ago

Why is the %age value changing from 40 to 140, 50 to 150 and 75 to 175 ?

Can anyone explain in detail please?

Can anyone explain in detail please?

Malli said:
1 decade ago

Because initial amount is 100 then 100+40=140 etc.

Praveen said:
1 decade ago

Any shortcut for this ?

Richa said:
1 decade ago

@ shwetha

when it is said that there is x% or y% increase in any value then to find out that increased value we have do

100+x

as in this example a value increased 40% means 100+40=140

when it is said that there is x% or y% increase in any value then to find out that increased value we have do

100+x

as in this example a value increased 40% means 100+40=140

Ramesh said:
1 decade ago

5:7:8 = 50:70:80

50*140/100=70 ; 70*150/100=105 ; 80*175/100=140

70: 105: 140 or

14: 21: 28 or

2: 3: 4

50*140/100=70 ; 70*150/100=105 ; 80*175/100=140

70: 105: 140 or

14: 21: 28 or

2: 3: 4

Hari said:
1 decade ago

Good shortcut ramesh.

Vivek mishra said:
1 decade ago

Thanks to giving a good salution with shortcut.

Sandi said:
1 decade ago

Very good shortcut ramesh.

Mariah said:
1 decade ago

Can we apply this shortcut for other problems?

Harjinder Singh said:
1 decade ago

1. 40% of 5 = 2, total seats 5+2=7

2. 50% of 7 = 7/2 total seats 7+7/2=21/2

3. 75% of 8 = 6 total seats 8+6=14

now compare ratios of all 7:21/2:14=>14:21:28

=>2:3:4

2. 50% of 7 = 7/2 total seats 7+7/2=21/2

3. 75% of 8 = 6 total seats 8+6=14

now compare ratios of all 7:21/2:14=>14:21:28

=>2:3:4

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