There are 10 girls and 20 boys in a class. The class has a test. The mean mark for all the class is 70.
The mean mark for all the boys is 62 Work out the mean mark for the girls.

Which expression is rational? 6. , square root two, square root 14, square root 49

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.

Simplify each expression. use positive exponents. show work . (x –2 y –4 x 3 ) –2