Answer:
0.2 [or 2/10 ; or 1/5]
Explanation:
100x = 1/10×200
100x = 20
÷100 ÷100
x = 0.2
check:
100 × 0.2 = 20
1/10 × 200 = 20
20 = 20
[true statement]
(Or, you know that 100 is half of 200, and to get from 100 to 200 we had to multiply by 2, and that 100 x 2/10 will be equal; this is harder to word though)