Mixing two kinds of candy the price of which was $2 and $4 per pound, Ella got a 10-lb mix of candy, which cost $2.90 per pound. How many pounds of each candy were used for the mix?

She bought 5.5lb of the $2 candy and 4.5lb of the $4 candy

Step-by-step explanation:

$2 × 5.5lb + $4 × 4.5lb = 10 lb × $2.90

  or  

step-by-step explanation:

if the four friends split the cost, p, of the pizza evenly, then each friend pays one-fourth of the cost of the pizza.

the expression is   or