Question

The mass of Book A is 645 grams and the mass of Book B is 925 grams. Find the total mass of ‘p’ copies of Book A and ‘q’ copies of Book B.

Answer 1

Hint: he mass of Book A is 645g and the mass of Book B is 925g.We need to multiply p with 645 grams and q with 945 grams to get the mass of ‘p’ copies of Book A and ‘q’ copies of Book B.

Complete step-by-step answer:
We are given that the mass of Book A is 645 grams and the mass of Book B is 925 grams. We need to find the total mass of ‘p’ copies of Book A and ‘q’ copies of Book B.
Given the mass of 1 copy of Book A=645 grams
Mass of 2 copies of Book A becomes $ 2 \times 645 = 1290 $ grams.
Mass of 3 copies of Book A becomes $ 3 \times 645 = 1935 $ grams.
In the same way the mass of ‘p’ copies of Book A becomes $ p \times 645 = 645p $ grams.
Given mass of 1 copy of Book B=925 grams
Mass of 2 copies of Book B becomes $ 2 \times 925 = 1850 $ grams.
Mass of 3 copies of Book B becomes $ 3 \times 925 = 2775 $ grams.
In the same way the mass of ‘q’ copies of Book A becomes $ q \times 645 = 645q $ grams.
Therefore, the total mass of ‘p’ copies of Book A and ‘q’ copies of Book B is $ \left( {645p + 925q} \right) $ grams.

Note: When we require the mass of ‘x’ no. of copies of an item, we just have to multiply the mass of 1 item with the number ‘x’. One can observe that actually linear equation in two variables is formed here in terms of p and q.