Question
The monthly incomes of A and B are in the ratio 3 : 4,
and their monthly expenditures are in the ratio 2 : 3. If each of them saves Rs. 4,000 per month, what is A’s monthly income?Solution
ATQ, Let incomes be 3a and 4a. Let expenditures be 2b and 3b. Savings: 3a − 2b = 4000 ...(1) 4a − 3b = 4000 ...(2) Multiply (1) by 3: 9a − 6b = 12000 Multiply (2) by 2: 8a − 6b = 8000 Subtract: (9a − 6b) − (8a − 6b) = 12000 − 8000 => a = 4000. A’s income = 3a = 3 × 4000 = Rs. 12,000.
A copper block of mass 3 kg is heated in a furnace to a temperature of 450°C and then placed on a large ice block. Find the maximum amount of ice that...
Which of the following is a characteristic of a conductor?
What is the unit of the refractive index?
What term refers to the superposition of two or more coherent waves to produce regions of maxima and minima?
A wire loop in the shape of a square of side a carries a current I. If an infinitely long straight wire carrying the same current passes through the ce...
If lift is going up with acceleration, the apparent weight of a body is -
A soap bubble shows colours when illuminated with white light. This is due to –
A silicon sample is doped such that the number of holes far exceeds the number of electrons. Which of the following is true about its conductivity?
A body is thrown vertically upward with a velocity of 20 m/s. What will be its velocity at the highest point?
In a concave mirror which of the following pair of position of object – size of the image is correct?
I. At infinity – point sized
