Valma gets paid $.30 per unit for all units produced up to 100.

For all units over l00, she gets paid $.42. How much did she earn
the day she produced 168 units?

Valma produced 100 units at $.30 each, which is:

100 x $.30 = $30

She produced an additional 68 units (168 - 100), which she gets paid at $.42 each:

68 x $.42 = $28.56

Therefore, she earned:

$30 + $28.56 = $58.56

To calculate how much Valma earned for producing 168 units, we need to consider two scenarios:

1. Units up to 100: Valma gets paid $0.30 per unit.
2. Units over 100: Valma gets paid $0.42 per unit.

First, let's calculate Valma's earnings for units up to 100:
Earnings for units up to 100 = (Number of units up to 100) x (Earnings per unit up to 100)
= 100 x $0.30
= $30

Next, let's calculate Valma's earnings for units over 100:
Number of units over 100 = Total units - Units up to 100
= 168 - 100
= 68

Earnings for units over 100 = (Number of units over 100) x (Earnings per unit over 100)
= 68 x $0.42
= $28.56

Now, let's calculate Valma's total earnings:
Total earnings = Earnings for units up to 100 + Earnings for units over 100
= $30 + $28.56
= $58.56

Therefore, Valma earned $58.56 the day she produced 168 units.