Previous their age was 21 and 18 respectively
Presently, after 6 years the age is 27 and 24.
30mins
Let the total time taken to fill the tank be x minutes.
Then, work done by B in half hour + work done by (A+B) in half hour =1.
(
40
1
×
2
x
)+(
60
1
+
40
1
)×
2
x
=1
⇒
80
x
+
48
x
=1
⇒
240
3x+5x
=1
⇒8x=240
⇒x=30 min
I have been teaching some students for 1 year.
e. 56 is 7*8 which is the product of 7 with even no.
around 29.8
Answer:
24
Step-by-step explanation:
A + B = 40.
And at Rs 7 a kg for 40 kg, you want a total of Rs.280.
So the second equation is 9A + 4B = 280
From the first equation: B = 40 – A
and sub into the second equation:
9A + 4(40-A) = 280
9A + 160 – 4A = 280
5A = 120
A = 24.
And you should check: B should equal 40-24 = 16. Check with the final equation: 9*24 + 4*16 = 216 + 64 = 280. So it works.
Your answer, of course, is A = 24
– While the train is moving, the jogger will also be running in the same direction.
– for the head(engine) of the train to get to the current position of the jogger 240m away, it will take:
45km/hr => 12.5m/s => 240/12.5 = 19.2 seconds.
– But in the same period of time, the jogger will still be running and will have moved to a new location by: 9km/hr => 2.5m/s => 2.5 * 19.2 = 48m
To get to the new location at the speed of 12.5m/s will take the train:
48/12.5 = 3.84sec
In this additional time, the jogger will move forward by:
3.84 * 2.5 = 9.6m
at a speed of 12.5m/s, it will take the train less than a second to cover the additional 9.6m
If we add the distance the jogger will cover in 1 second to 9.6, it is still less than what the train can cover per second. let us see (9.6 + 2.5 = 12.1)
Therefore, the head of the train will pass the runner at approximately: 19.2 + 3.84 + 1 => 24.04 seconds.
For the train to completely pass the runner, it will need its whole length of 120m to be in front of the runner.
This will take an additional (9.6 + 2) seconds.
Therefore for the length of the train to be ahead of the runner it will take approx. 35.65 (24.04 + 9.6 + 2) seconds
190.85
79.2
60000
x:y=18:11