Answer:
The total cost of the helicopter = $26.5
The cost of lithium battery = $5.
The amount of sales tax = $1.5
Step-by-step explanation:
We have been given that a radio-controlled helicopter sells for $20, but needs a lithium battery that costs 25% of that price.
We can find the price of battery by finding 25% of 20.



Therefore, the cost of lithium battery is $5.
Now let us find the sales tax on the cost of helicopter and lithium battery.



Therefore, the total sales tax will be $1.5.
We can find the total cost of helicopter by adding the cost of helicopter, cost of lithium battery and total amount of sales tax.


Therefore, the total cost of helicopter will be $26.5.