Aptitude - Ratio and Proportion - Discussion

Will the percent increase not be 40/100 into 5x + 5x and so on?

As this is increased percentage?

We are given --> M : P : B = 5:7:8 . Increased in seats by 40% , 50% & 75%.
So this we can write as M:P:B = 5x : 7x: 8x (assuming common multiplier be x)
for simplicity of answering i am assuming x as 10.
So Before Increase Math seats = 5*10 = 50.
Similarly , Physics = 70 & Biology = 80.

Now Comes the increasing part.
Math by 40 % = 50*40/100 = 20.
So New Seats for math = (Earlier Available + New Seats) (50 + 20) = 70 Seats.
Similarly For physics it will be by 50 % = 70 * 50/100 = 35 & New Seats = 70+35 = 105.

For Biology New seats would be = 140.
After calculation, New Seats Are 70 : 105 : 140.
Simplify It & Answer would be 2:3:4.

For make calculation easy take the values as 500 : 700 : 800,

40% of 500 =200,
50% of 700 =350,
75% of 800=600,
Then the increased ratio = 700 :1050:1400.

After simplification, the answer would be 2:3:4.

Awesome, thanks @Ramesh.

Seats for maths, science and arts in a school are in the ratio 5:7:8.there is a proposal to increase these seats by x%, y%, z% respectively. And the ratio of increased seats is 2:3:4. Find x, y, z.

Can anyone solve this?

If it's decreasing to 40% then what is the answer?

Thanks for the answer @Harjinder.

7 : 8 = 50 : 70 : 80 then
40% :50% :75% = 70 : 105 : 140.

So, 14 : 21 : 28 = 2 : 3 : 4 is the answer.

Only increased seats?

How is it possible? Please tell me.

@All.

Would this formula be applicable if the number of seats is to be DECREASED rather than INCREASED?

And the ratios themselves are decreasing after solutions, how then the seats were increased? could anyone tell me why the ratios decreased instead of increasing?