Let the person who digs the sand be X and the person who transports the sand be Y, because in order to transport the sand away.
So the tonnage of dredging and transporting sand should be the same, so
4*X=5*Y
Because 27=X+Y Y=27-X, so
4*X=5*(27-X)
4 X/5 = 27 X
4*X/5+X=27
9 X 5 = 27
X= 15
Because formula 4*X=5*Y
So 4* 15=5*Y
Y= 12
The answer is 15 people dig sand and 12 people transport sand.
2) If the speed of A is X, then the speed of B is x-2, because A is faster than B 10 meter for 5 seconds.
2(x-2)+4(x-2)=4x
The solution is x=6 x-2=4.
A: A is 6 and B is 4.