The mean life of a tire is 30,000 km. The standard deviation is 2000 km. 95% of all tires will have a life between___ km and ___km.

Between 26,000 and 34,000 km.

Step-by-step explanation:

95% of a data set will be within 2 standard deviations of the mean.

Therefore, the range will be from "μ - 2σ" to "μ + 2σ".

mr. flanders’ class sold 47 doughnuts and   mr. rodriquez’s class sold 38 cartons of milk

step-by-step explanation:

let x be the number of doughnuts sold by mr. flanders’ class and y be the number of cartons sold by mr. rodriquez’s class.

1. together, the classes sold 85 items, then

x+y=85.

2. both classes earn earned $104.49 for their school. if doughnuts were sold for $1.35 each, then x doughnuts costed $1.35x. if cartons of milk were sold for $1.08 each, then y cartons costed $1.08y. hence,

1.35x+1.08y=104.49.

3. solve the system of two equations: