Question 1084132
d+n =74 subtract d from both sides:
n = 74-d
0.10d+0.05n = 4.70 substitute for n:
0.10d+0.05(74-d) = 4.70
0.10d+3.70-0.05d = 4.70
0.05d = 1
d = 20
n = 74-20 = 54