Chapter 7: Algebra

Solution:-

Number of pencils bought for Rs x at the rate of Rs 2 per pencil is x/2.

From the question it is given that, cost of pencil = ₹ x

No. of pencils bought for ₹ 2 = 1

Therefore, number of pencil bought for ₹ x = ₹ x/2

Solution:-

The number of days in w weeks is 7w.

We know that, there are 7 days in a week.

Therefore, number of days in w weeks is 7w.

Solution:-

Annual salary at r rupees per month along with a festival bonus of Rs 2000 is ₹12r + 2000.

From the question it is given that,

Salary per month is r rupees

A festival bonus of ₹ 2000

Therefore, the annual salary at r rupees per month along with a festival bonus of Rs 2000 is ₹ 12r + 2000

Solution:-

The two digit number whose ten’s digit is ‘t’ and units’s digit is ‘u’ is 10t + u.

From the question,

Two digit number whose ten’s digit is ‘t’

Two digit number whose unit’s digit is ‘u’

Then, the number = 10 × t + 1 × u

= 10t + u

Solution:-

The variable used in the equation 2p + 8 = 18 is p.

The word ‘variable’ means something that can vary, i.e., change. The value of a variable is not fixed. We use a variable to represent a number and denote it by any letter such as l, m, n, p, x, y, z etc

Solution:-

x metres = x × 100 centimetres

We know that, 1 metre = 100 centimetre.

Therefore, x metres × 100 centimetres = 100x centimetres

Solution:-

p litres = p× 1000 millilitres

we know that, 1 litre = 1000 millilitres

Therefore, p litres × 1000 millilitres = 1000p milliliters.

Solution:-

r rupees = 100r paise

We know that, 1 rupee = 100 paise

Therefore, r rupees = 100r paise

Solution:-

If the present age of Ramandeep is n years, then her age after 7 years will be n + 7 years.

Solution:-

If I spend f rupees from 100 rupees, the money left with me is 100 – f rupees.

In questions 41 to 45, state whether the statements are true or false.