Can someone explain to me how to work this out ?

Two blends of tea are mixed to make a blend that will be sold at the fair. black tea sells for $2.20 per pound and orange pekoe tea sells for $3.00 per pound. how much of each should be used to obtain a 4lb blend selling for $2.50 per pound?

Eliza wants to make $10,000 from her investments. she finds an investment account that earns 4.5% interest. she decides to deposit $2,500 into an account. how much money will be in her account after 14 years?

If log(a) = 1.2 and log(b)= 5.6, what is log(a/b)? a. 4.4b. 6.8c. not enough informationd. -4.4