Answer:
93.75
Explanation:
In first half life 750×1/2 will remain
In second one half from that remained at the end of first half life will remain
That is 1/2 × 750×1/2
likewise at the end of 3rd half life 1/2 × 1/2 ×750×1/2 remains
at the end of 4th half life 1/2 × 1/2 × 1/2 ×750×1/2 remains
1/2 × 1/2 × 1/2 ×750×1/2 = 93.75 remains.
You can also use the equation
Remainder = X × 1/2^n .
This saves time
n= no. of half lives
X= initial amount
so in this case 1/2^4 × 750 = 93.75
