3. 1 per 4 + 0,15 × 4 per 5 : 5%

(3 1/4+ 15/100)x(4/5÷5/100)= 76

1/4 + 0,15 × 4/5 : 5%
= 1/4 + (3/20 × 4/5) : 1/20
= 1/4 + 12/100 : 1/20
= 1/4 + (3/25 : 1/20)
= 1/4 + (3/25 × 20/1)
= 1/4 + 60/25
= 1/4 + 12/5
= 1/20 + 12/20
= 13/20