What is the unit rate 3 for $5 4 for$6

The unit rate for 3 for $5 is around $1.70 or $1.60

The unit rate for 4 for $6 is $1.50

You have two separate problems here.

a) 3 for $5 needs to be expressed as cost per unit. Write $5 / (3 units), and then simplify. Here the unit rate is ($5/3) / unit, or $1.67 per unit.

b) 4 for $6: Write $6 / (4 units), and then reduce to lowest terms:

(6/4) dollars per unit, or $1.50/unit