The numerical expression to find the cost of the apples and bananas is (4 x 0.50) + (1 x 0.80) and the cost is $2.80.
Sylvia bought 4 bananas and it cost her 50 cents each. She also bought an apple which cost her 80 cents.
The total cost in dollars is:
= Cost of bananas + Cost of apples
= (Number of bananas x Cost of each banana) + (Cost of apple x Cost of each apple)
= (4 x 0.50) + (1 x 0.80)
The cost would be:
= (4 x 0.50) + (1 x 0.80)
= $2.80
In conclusion, the cost of the apples and bananas would be $2.80.