You start with the equation 5z=20. Your friend changes the left side as follows. 5z+2= ?
What should you do to the right side so a solution of the original equation is also a solution of the new equation?

1. Add 2 to 20.
2. Subtract 2 from 20.
3. Add 5z to 20.
4. Subtract 5z from 20

The radius of the earth is two times the radius of the moon. what fraction of the volume of the earth is the volume of the moon?

Martha has a deck of cards. she has lost some of the cards, and now the deck only contains nine spades, eleven diamonds, eight clubs, and twelve hearts. martha predicts that whenever she draws a card from the deck without looking, she will draw a club one-fifth of the time. which activity would best allow martha to test her prediction? a. randomly draw a card from the box and see if it is a club. b. randomly draw a card. then, continue to draw another card until all eight clubs are drawn. c. randomly draw and replace a card 120 times. then, observe how close to 30 times a club is drawn. d. randomly draw and replace a card 100 times. then, observe how close to 20 times a club is drawn.

There were 25 students who answered to a survey about sports. four-fifths of them like football. how many students like football?