Let the amount of money Nell have = N,
And the amount of money David have = D
Nell David
Initiallly N D
Case 1 N - 16 D + 16
Case 2 N + 9 D - 9
Case 1 --> When Nell gives David $16,
Then both have the same amount.
So, N - 16 = D + 16
N = D + 16 + 16 = D + 32
Case 2 --> When David gives Nell $9,
Nell and David's amount will be in
The ratio 6:1.
(N + 9)/D - 9 = 6/1
N + 9 = 6D - 54
N = 6D - 63
After equating the equations from both cases,
We will get N => D + 32 = 6D - 63
32 + 63 = 6D - D
95 = 5D
D = 95/5 = $19
And, N = D + 32
Nell have $51 and David have
$19. Together they have $(51 + 19)
= $70