Twenty million four hundred eighty four thousand one hundred sixty three
$1400 / 7 = $200
$200 x 2 = $400
$1400 - $400 = $1000
John has $1000 left in his account.
The speed of the ball is
ds/dt = 32t
At t =1/2 s
ds/dt = 16 ft/s
The distance from the ground
50 - 16(1/2)^2 = 46 ft
The triangles formed are similar
50/46 = (30 + x)/x
x = 345 ft
50 / (50 - s) = (30 + x)/x
Taking the derivative and substituing
ds/dt = 16
and
Solve for dx/dt