Question

Rekha has 15 square colour papers of sizes 10cm, 11cm, 12cm ……. 24cm. How much area can be

decorated with these colour papers?​

Answer 1

Step-by-step explanation:

area of these papers collectively=10^2 +11^2+13^2+.......+24^2

1^2+2^2+3^2.....+n^2=n (2n+1) (n+1)/6 this is the sum of such a series with n terms

sum of given series=(1^2+2^2+3^2......+24^2)-(1^2+2^2+3^2....+9^2)

=24(24×2+1) (24+1)/6 - 9(2×9+1) (9+1)/6

=4615 cm^2