Inessa = X
Ralph = Y
By the given ratio X/Y = 5/6
Solve for X: X = 5/6 * Y
Now Inessa gives 1/2 of hers to Ralph, which then totals 850"
Y + 1/2X = 850
Replace x :
Y + 1/2 * 5/6 * Y = 850
SImplify:
Y + 5/12Y = 850
Multiply both sides by 12 to remove the fraction:
12Y + 5Y = 10200
Simplify:
17Y = 10200
Divide both sides by 17:
y = 10200 / 17
y = 600
Ralph originally had 600 plants.