Salut! :)
1. a) 36% = 36/100 (⁴ = 9/25
2. a) 3/5 × 105 = 3 × 21 = 63
2/7 × 63 = 2 × 9 = 18
b) 75/100 × 1600 = 75 × 16 = 1200
15/100 × 1200 = 15 × 12 = 180
c) 30/100 × 500 = 30 × 5 = 150
3/5 × 150 = 3 × 30 = 90
d) 5/7 × 350 = 5 × 50 = 250
29/100 × 250 = 29/10 × 25 = 2,9 × 25 = 72,5
3. a) 30/100 × 60 = 3 × 6 = 18
25/100 × 50 = 25/2 = 12,5
18 + 12,5 = 30,5
b) 2/9 × 180 = 2 × 20 = 40
4/7 × 280 = 4 × 40 = 160
40 + 160 = 200
c) 15/100 × 120 = 15/10 × 12 = 15/5 × 6 = 3 × 6 = 18
1/37 × 185 = 5
18 + 5 = 23