Acity has 4 new houses for every 9 old houses. if there are 28 new houses in the city, how many old houses are there?

Need on this one asap im almost done with this subject

Acolony contains 1500 bacteria. the population increases at a rate of 115% each hour. if x represents the number of hours elapsed, which function represents the scenario? f(x) = 1500(1.15)" f(x) = 1500(115) f(x) = 1500(2.15) f(x) = 1500(215)

What expression is equivalent to (84+16)