Answer:
Charlie should use a stopwatch with minutes and seconds
Step-by-step explanation:
charlie should not count in his head as it is not accurate, he could count too fast or slow
Charlie should not look at that clock and the seconds will affect the 25 minutes, whether it be less or more
Charlie should not use an hourglass as he might flip it over too soon or quick and it's not very accurate
therefore using the stopwatch allows him to accurately and fairly keep track of the exact time
Lets Anna's age = A
Mr. Goldstein age = G
Mr. Goldstein is 4 times as old as his daughter Anna.
So G= 4A
In 4 years, he will be 3 times as old as Anna
we add 4 with Both their ages
G + 4 = three times of A + 4
G + 4= 3(A + 4)
We know G= 4A, replace it in above equation
4A + 4= 3(A + 4)
4A + 4= 3A + 12
Subtract 3A from both sides
A + 4 = 12
Subtract 4 from both sides
A = 8
So Anna's age = 8 years
