Question

107. A 500 g of toothpaste sample has 0.2 g
fluoride concentration. What is the
concentration of fluoride in ppm?
(a) 250 (b) 200
(c) 400 (d) 500

Answer 1

Answer:

400

Explanation:

As we know that only .2 g of fluoride is there out of 500 g

i.e

.2= 500

2 = 5000

if 2 particles of fluoride is available in 5000 g of toothpaste

now particles per million

5000× 200 = 2×200

1000000= 400

so the answer is 400

also we can calculate easily

if 0.2 = 500

the 1000000 = ?

1000000/500×0.2

10000/5×0.2

2000×O.2 = 400 ✓✓