Question

question number 9 only (it start with Nalini from Simple Interest chapter.)

Answer 1

si=
$\frac{pnr}{100}$
=
$\frac{550 \times \frac{2}{3} \times 8 }{100} \\ = \frac{88}{3} = 29.3$
she paid 29.3+550
=579.3