Can I please get help with the answer I don’t understand

Amerchant has coffee worth $60 a pound that she wishes to mix with 50 pounds of coffee worth $90 a pound to get a mixture that she will sell for $70 a pound. how many pounds of the & 60 coffee should be used?

Choose the number sentence that shows the identity property of addition. a. 122 = 61 + 61 b. 62 = 1 + 61 c. 61 = 0 + 61

Aball is dropped from a height of 10m above the ground. it bounce to 90% of its previous height on each bounce. what is the approximate height that the ball bounce to the fourth bounce?