Stella has 215 coins and 89 of them are nickels. Two-thirds of the remaining coins are pennies. How many pennies does Stella have? A. 38
B. 42
C. 66
D. 84

84

Step-by-step explanation:

215 - 89 = 126

126 divided by 3 = 42

42 x 2 = 84

( this was how my teacher taught me to do these kind of problems)

Hope this helps! <3

he spend 5.1 minutes chatting with his friends.

step-by-step explanation:

2/5+1/2=9/10

6/1-9/10=5.1

because linear equations are a lot simpler than quadratics equations, and linear equations formula is a lot easier to memorize. that's why i think they're harder.