DELHI POLICE MATHS QUIZ-48

If in 3 years a sum of ₹ 1,900 becomes ₹ 2,100 at a certain rate of simple interest, then in 5 years at the same rate of interest ₹ 11,400 will become?

The average weight of a certain number of persons in a group is 78 kg. If 4 persons having average weight 80.75 kg leave the group, the average weight of the remaining persons becomes 77.725 kg. The number of persons, initially, is:

A, B and C can do a piece of work in 10,12 and 15 days, respectively. In how many days can B do the work, if he is assisted by $A$ and $C$ together on alternate days?

When $x$ is added to each of $6,12,18$ and 28, the numbers obtained in this sequence are in a proportion. What will be the value of $(5 x-8):(x+4)$?

If $\mathrm{a}=(5 / 4) \mathrm{b}$ and $\mathrm{b}=(2 / 10) \mathrm{c}$, then what is $\mathrm{a}: \mathrm{b}: \mathrm{c}$ ?

The seats for Mathematics, Physics and Computer Science in a school are in the ratio 7:8:9. These seats are proposed to be increased by 60%, 50% and 70% respectively. What will be the ratio of increased seats ?

A passenger train without stoppages runs at an average speed of $75 \mathrm{~km} / \mathrm{h}$, and with stoppages, at an average speed of 60 $\mathrm{km} / \mathrm{h}$. What is the total time (in hours) taken by the train for stoppages on a route of length $600 \mathrm{~km}$ ?

A boat takes 14 minutes to travel $8.4 \mathrm{~km}$ upstream. If the ratio of the speed of the boat to that of the stream is $6: 1$, then how much time (in minutes) will the boat take to travel $33.6 \mathrm{~km}$ downstream?

The curved surface area of a right circular cylinder is $1320 \mathrm{~cm}^{2}$ and the radius of its base is $10.5 \mathrm{~cm}$. The volume (in $\mathrm{cm}^{3}$ ) of the cylinder is: (Take $\pi=\frac{22}{7}$ )

The area of a triangular field with sides $120 \mathrm{~m}, 182 \mathrm{~m}$ and $218 \mathrm{~m}$ is equal to the area of a rectangular garden whose sides are in the ratio $14:13$. What is the perimeter of the garden (in $\mathrm{m}$)?