You buy a hamburger for $7.50 and a soda for $3.50 you have to pay a 8% tax and then you want to leave a 15% tip how much will you pay in total

$13.66

Step-by-step explanation:

First, find the total cost of things.

Hamburger + Soda = 7.50 + 3.50 = 11.00

Next, calculate the cost with tax.

tax = 11.00 * 0.08 = 0.88

cost with tax = 11.00 + 0.88 = 11.88

Finally, calculate the cost with tip.

tip = 11.88 * 0.15 = 1.78

cost with tip and tax = 11.88 + 1.78 = 13.66

300 Hz

Step-by-step explanation:

Something may be wrong on my end because I only see a question labeled 5. Anyways, you can basically just follow the units here.

So in order to use the given info to get the correct units...

Plugging in or knowns gives us:

Frequency = (120/.4) = 300 Hz

This might be an informal way to think about it technically but it's a good way to do it nonetheless.