Answer:
you've go to find 1% first so do 2,500 divided by 100 = 25
now to find 4% you have to multiply 25 by 4 = 100
after 3 years you just multiply 100 by 3 and add to the account total = 2500 plus 300 = 2800
after 16 yrs you multiply 100 by 16 = 1600 = 2500 + 1600 = 4100
for the target of 3000 you need 500 more dollars so you would simply multiply 5 by 100 to get 500 and this would get you to 3000 = 5 years to get to 3000
for 3500 you need 1000 so multiply 100 by 10 which would = 4500 so 10 years
hope this helps