Q# 5, 6. Find the cost of a) 10 kg of tea leaves when 3 kg of tea leaves cost $18

 

 

5. Find the cost of

a) 10 kg of tea leaves when 3 kg of tea leaves cost $18

Tea leaves and cost is directly proportional if leaves increases, cost will also increase so

  X ∝ Y (∝ symbol of directly Proportion)

Y = KX (Where K is constant)

let 

tea leaves=X

cost=Y

18 = K × 3

K = 18/3

K = 6

X = 6Y

X = 6 × 10

X = $60

(Cost of 10 kg is $60)

b) a Kg of sugar when b kg of sugar cost $c.

b kg sugar cost $c

1 kg of sugar cost c/b

a Kg of sugar cost = a × c/b

a = $ac/b

6. 5/9 of a piece of metal has mass of 7 kg what is the mass 2/7 

5/9 = 7kg

1m=7÷5/9

1m=7×9/5

1m=63/5

mass of 2/7=63/5 × 2/7

mass of 2/7=18/5

mass of 2/7=3