Question

a boy gets rupees 20 per month as pocket money and spends only 71% of it how much will be save in one year​

Answer 1

short tricks,

100% = 20

1% = 20/100

= 1/5

71% = 1/5 * 71 = 14.2

so

save money = 20 - 14.2 = 5.8 rupees