Brad needs (30.1 + 37.5 + 14.8 + 10.01 + 15.2) = 107.61 cm of wood.
How many lengths does he need in order to have 107.61 cm of wood ?
(107.61 cm) / (35 cm/length) = 3.075 lengths
3 lengths is not quite enough. But it's only sold in whole lengths of 35 cm.
So in order to cover that last little smidgen, he'll need to buy 4 lengths.