1/10 + 1/12 -1/20 = 15/2 i.e 7.5 h means 7 h & 30 min
1/32(x)L=21h
10L=1h
X=21x10x32
=6720 Liters
Thus:
6720L=Yh
10L=1h
Yh=6720/10
Y=672h
24 Kmp/h
995
Let’s assume the length of each train is ‘L’ and the speeds of the two trains are ‘V₁’ and ‘V₂’ respectively.
When the trains are moving in the opposite direction, their relative speed is the sum of their individual speeds. The total distance they need to cover is the sum of their lengths. Since they cross each other completely in 5 seconds, we can set up the following equation:
(V₁ + V₂) × 5 = 2L
When the trains are moving in the same direction, their relative speed is the difference between their individual speeds. The total distance they need to cover is the difference between their lengths. Since they cross each other completely in 15 seconds, we can set up the following equation:
(V₁ – V₂) × 15 = 2L
Now, let’s solve these equations to find the ratio of their speeds.
From the first equation, we have:
(V₁ + V₂) × 5 = 2L
V₁ + V₂ = (2L) / 5
From the second equation, we have:
(V₁ – V₂) × 15 = 2L
V₁ – V₂ = (2L) / 15
Let’s add these two equations together:
V₁ + V₂ + V₁ – V₂ = (2L) / 5 + (2L) / 15
2V₁ = (6L + 2L) / 15
2V₁ = (8L) / 15
V₁ = (4L) / 15
So, the speed of the first train is (4L) / 15.
Now, let’s substitute this value back into the first equation to find V₂:
(4L) / 15 + V₂ = (2L) / 5
V₂ = (2L) / 5 – (4L) / 15
V₂ = (6L – 4L) / 15
V₂ = (2L) / 15
Therefore, the speed of the second train is (2L) / 15.
The ratio of their speeds is given by:
(V₁ / V₂) = ((4L) / 15) / ((2L) / 15)
(V₁ / V₂) = 4L / 2L
(V₁ / V₂) = 2
So, the ratio of their speeds is 2:1.
let x be the avg age of each person in the family ten years
back…
so total age=6x
after 10 years i.e,now the total age of the family =6x+60
let grand father age as y
then the average of the family=(6x+60-y)/5
(bcoz grand father has expired and the new born baby has no
age at present)
according to the given question (6x+60-y)/5=x
bcoz x is the avg age bfore 10 years.
while calc the equation according to the presnt age we have
to add 10 to the result….
so the answer is 70
22
Statements :
Some kings are queens. All queens are beautiful.
Conclusions :
I. All kings are beautiful.
II. All queens are kings.
Conclusion 1 follows
A certain sum amounts to Rs. 1725 in 3 years
and amounts to Rs.1875 in 5 years
so interest of 2 years = 1875 -1725
= 150
so interest of 1 year = 75
so interest of 3 years = 75 × 3 =225 rs
so , Principal = Amount – SI
= 1725 – 225
= 1500 rs
now ,
S.I. = P × N × R /100
75 = 1500 × 1 × R /100
R = 75 / 15
R = 5%
151
B
3630
no