A rectangle pile foundation has been designed in 7 rows and there are 5 piles in each row. The diameter of the piles is 80 cm, the length of the piles is 10 m. The pile foundation is in a 15 m deep coarse sand layer. The spacing between the piles is 1.5 m. 

a)If one pile can carry 1.5 t, what would be the total load that the foundation can carry? 

b)what if the lenght was 20 m and the layer was 40 m soft clay layer, assume that each carries 1.2 t, what woluld be the total load? 

Calculate approximately. If necessary use pile efficiency formulas