21
90 inches
Slab = 6(x) where x is each step
Slab = 5(x + 3)
6(x) = 5(x + 3)
6(x) = 5(x) + 15
x = 15 inches
So 6(x) = 6(15) = 90
Check: 5( x + 3) = 5(18) = 90
Slab size is 90 inches
2^a = 2 x 2+a
a^3= 2 x a + 3
=> 4+a= 2a + 3
=> a = 1
7
let the amount of money be x
cloths 1/3 X x=rs.x/3
balance = x- x/3 = 2x/3
food = 1/5 X 2x/3 = 2x/15
balance = 2x/3 – 2x/15= 8x/15
travel = 1/4 X 8x/15 = 2x/15
now he has 100 rupees
2x/5 = 100
2x= 500
x = 500/2
x = 250
9
3;4
Which means the train will travel 180 m in 6 seconds so
We need to convert this into minutes
6×10 = 60s= 1 minute.
180×10 = 1800 m train will travel 1.8 km in 1 minute.
1.8×60 = 108 kmph
225
A
let’s say the Cost Price is 1000x. (CP)
The selling price is also the same as the Cost price. So, here SP=CP (But he sells 950gm instead of 1000gm)
Instead of 1000gm, he is selling 950 grams at the CP. So he sells 050 gms @1000x price. So his net profit is 50gm.
Now 1000gm is 1000x Rs
So, 50gms is 50x rs. [Apllied Unitary Method]
So his profit percentage is:
Profit Percentage Formula: {(Profit/CP)*100%}
So, Here profit is 50x;
CP is 1000x;
so putting the value in the formula we get, Profit Percentage is: (50x/1000x)*100% =(5000x/1000x)%=5%.
Speed of train = 54km/hr
= 54 x (5/18) m/s
= 15 m/s
Length of train = 165m
Time required to cross a bridge of 660m in length = (660+165) / 15
= 55 seconds
Matches played: 60.
Matches won: 30% of 60 => (60*(30/100)) = 18 matches.
Iterative approach:
On adding 1 to matches played and matches won, on every iteration until the win percentage gets to 50. So
19 / 61 = 0.3114754098360656
20 / 62 = 0.3225806451612903
21 / 63 = 0.3333333333333333
22 / 64 = 0.34375
…
…
…
…
Similarly,
41 / 83 = 0.4939759036144578
42 / 84 = 0.5
So, after 60th match 24 more matches has to be played and won to get 50% average winning rate.
The answer cannot be determined as there is a particular formula where the consecutive numbers start.
5A=3B,
*3 SO,
15A=9B