Answer: Option B
:
B
Consider 0.9, it is greater than 0.7 as well as 0.3, hence it cannot lie between 0.3 and 0.7. Similarly,0.2 and 0.8 cannot lie between 0.3 and 0.7.
But, 0.4is greater than 0.3 and less than 0.7. Hence, it lies between 0.3 and 0.7.
OR
0.2 has 2 tenths, 0.3 has 3 tenths, 0.4 has 4 tenths, 0.7 has 7 tenths, 0.8 has 8 tenths and 0.9 has 9 tenths.
2 tenths$<$3 tenths$<$4 tenths$<$7 tenths$<$8 tenths$<$9tenths
$⟹0.2<0.3<0.4<0.7<0.8<0.9$
Thus, 0.4 lies between 0.3 and 0.9.