We take reference to the centre of the wheel, which is the only point "not rolling" at all in the wheel.

The distance "rolled" by the wheel
= 5 revolutions
= 5 circumferences worth of rolling
= 5 x circumference
= 5 x pi x diameter (or 5 x 2 x pi x radius, if you prefer)
= 5 x 22/7 x 70 (or 5 x 2 x 22/7 x 35)
= 1100 cm

In other words, the centre of the wheel would have moved 1100 cm to the right to hit wall B. Note, however, that the centre of the circle does not start at wall A and does not end at wall B.

When the wheel touches wall A, the centre of the wheel is 35 cm AFTER wall A. When the wheel touches wall B, the centre of the wheel is 35 cm BEFORE wall B.

As such, we need to add the two groups of 35 cm each to find the additional length.

Length of wall
= 1100 + 35 + 35
= 1170 cm

[In other words, out of the 1170 cm distance between the wall, 70 cm is for the size of the wheel and 1100 cm is the rolling distance of the wheel]