Working together, Lex and Rog pick 210 very big radishes
in 6 minutes.
Working alone, QuickdrawLex can pick 210 very big radishes
in 5 less minutes than SlowpokeRog.

And now for the 64 cents question:
how many minutes does it take Rog when working alone?

Why SlowpokeRog takes 5 more minutes than QuickdrawLex to pick 210 very big radishes

A thorough investigation revealed that Rog
wasted time eating a few of them delicacies;
he brought along one of Mrs W's damp kitchen
dishcloth to clean 'em...

Working alone, it takes Rog 15 minutes

t = minutes for Rog to pick 210 radishes
t-5 = minutes for Lex to pick 210 radishes
vR = speed at which Rog works
vL = speed at which Lex works

Working separately,
210 = vRt
210 = vL(t-5)

Working together,
210 = 6vR+6vL = 210(6)/t + 210(6)/(t-5)
1 = 6/t + 6/(t-5) = (12t-30)/(t^2-5t)
t^2-17t+30 = 0
(t-2)(t-15) = 0
t = 15 minutes

Yepper CCB!!
I prefer yours to mine!

L = Lex, R = Rog

During 1 hour:
L alone: 1/x of job
R alone: 1/(x+5) of job

L and R together: 1/x + 1/(x+5) = (2x+5) / (x(x+5)) of job

Let t = total time:
(2x+5) / (x(x+5)) = 1/t
t = (x(x+5)) / (2x + 5)
Since it is given that total time together = 6:
(x(x+5)) / (2x + 5) = 6

(x(x+5)) = 6(2x+5)

x^2 + 5x = 12x + 30

x^2 - 7x - 30 = 0
(x - 10)(x + 3) = 0
x = 10

So Rog = 10 + 5 = 15 minutes