I need help on my IXL

Start:
348 + 580 = 928
348/928 = .375 x 100 = 37.5% with narrow shells
580/928 = .625 x 100 = 62.5% with round shells
End: 564 + 236 = 800
564/800 = .705 x 100 = 70.5% with narrow shells
236/800 = .295 x 100 = 29.5% with round shells

When rates are expressed as a quantity of 1, such as 2 feet per second or 5 miles per hour, they are called unit rates. if you have a multiple-unit rate such as 120 students for every 3 buses, and want to find the single-unit rate, write a ratio equal to the multiple-unit rate with 1 as the second term.