The speed of a bus increases by 22 kmph after every one hour. If the distance travelled in the first one hour was 3535 km, what was the total distance travelled in 1212 hours?
He travels 2020 km more due to an increase of speed of 44 km/hr. Hence, with 1010 km/hr, he travels 20/4×10=50 km.
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A man goes to his office from his house at a speed of 3 km/hr and returns at a speed of 2 km/hr. If he takes 5 hours in going and coming, what is the distance between his house and office?
A man complete a journey in 10 hours. He travels first half of the journey at the rate of 21 km/hr and second half at the rate of 24 km/hr. Find the total journey in km.
Three cats are roaming in a zoo n such a way that when cat A takes 5 steps, B takes 6 steps and C takes 7 steps.But the 6 steps of A are equal to the 7 steps of B and 8 steps of C. what is the ratio of their speeds?
Therefore, Ratio of speeds of A, B and C = 5/6 : 6/7 : 7/8 = 140 : 144 : 147
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The ratio of the number of boys and girls in a college is 7 : 8. If the percentage increase in the number of boys and girls be 20% and 10% respectively, what will be the new ratio?
Vipin can walk a certain distance in 52 days when he rests 10hours a day.how long will he take for twice the distance if he walks twice as fast as and rest twice as long each day
Vipin rests for 10 hours a day. As there are 24 hours in a day, the time he walks is 24 – 10 = 14 hours.
Total time taken = 52days X 14 = 728 hours
As distance is directly proportional to time, to cover double the distance he needs double the time.
That is, 2 x 728 hours.
But, as speed is inversely proportional to time and directly proportional to distance, double distance will require double speed.
That is, total time is
2/2 x 728 = 728 hours.
In the new situation, he rests for twice as much that is,
10 x 2 = 20 hours. Therefore he only walks for 24 – 20 = 4 hours.
If the number of days required is x,
4x = 728
x = 728/4
= 182 days
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One year ago a father was four times as old as his son .after 6 year his age exceed than twice of his son age by 9 year. Ratio of their present age is what
Lets denote the ages of the man and his son as M and S respectively.
One year ago their ages were M – 1 and S – 1 respectively.
So from the first statement, M – 1 = 4 * (S – 1) or
M – 4*S = -3 ← Equation 1
In 6 years time both would be older by 6 years, or M+6 and S+6.
From the second statement,
M + 6 = 2 * (S +6) + 9, or
M – 2*S = 15 ← Equation 2
Subtracting Equation 1 from Equation 2, we get:
M – 2*S – (M – 4*S) = 15 – (-3)
That is, 2*S = 18 , or S = 9. Therefore the Son’s present age is 9.
From Equation 2, M = 15 + 2*S or M = 15 + 18 = 33.
Therefore the Father’s present age is 33.
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An alloy of copper and tin weighing 1kg consist of 70% copper, how much copper should be added to it so that it would contain 75% copper? What will be the weight of the new alloy?
Suppose that x kg copper is to be added to the 1 kg alloy.
Now, we know that, the 1 kg alloy has 0.7 kg copper.
And, final percentage of copper in alloy is 75%.
(0.7+x)/(1+x)=75/100=3/4(0.7+x)/(1+x)=75/100=3/4
On cross-multiplication,
2.8+4x = 3+3x
x= 0.2
Therefore,
0.2 kg or 200 g copper should be added to make it’s percentage in the alloy 75%.
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The ratio of the number of boys to the number of girls in a class is 4:5. If there are a total of 54 students in the class, then what is the number of boys in the class?
It is 3:2 I feel because on adding all the ratios only 3:2 results in 5 i.e 3+2=5 and 5 is not a factor of 12
Or
Here your first option is 2:1
Now splitting 12 in the Ratio 2:1 we get 8 and 4. So, it is possible.
Next you have 3:1 this is also possible ratio as it can be 9 and 3.
Now if we look at 3:2 then it is obviously not possible to split 12 into ratio of 3 and 2.
But still for last one we have7:5 this makes a total of 12. So 7 broken and 5 unbroken is also possible.
So, the correct answer is 3:2.
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The incomes of A,B and C are in a ratio of 7:9:12 and the expenditures are in a ratio of 8:9:15. If A saves 1/4 of its income then what will be the saving ratio of A ,B and C?
