5 questions below with work shown please

21 If some isotope has a half-life of 24 seconds and initially there are 40 grams present, how much will be left after 48 seconds? 22 How long does it take for an investment of $1000 to triple at an interest rate of 7% if the interest is compounded biannually? Soutony bilt isday 23 What principal must be invested at an interest rate of 4% to yield $4000 in two years if the interest is compounded continuously? A ed novigeal joubert mariog m 24 If an object's temperature is given by T = 30 + 20e-0.1, where t is in minutes, how long . does it take for the temperature of the object to reach 40 degrees? = Nol ghilogon zesaruangst zon annimut schol esla di atbay to isdern ardi ball 25 If a population model has P = 10,000(2) 20, how long does it take for the population to reach 15,000