Acertain substance x decomposes. it is found that 50% of x remains after 100 minutes. how much x remains after 200 minutes if the reaction order with respect to x is

The time needed for a substance becomes half of it mass is called half-time, after. In this case, the half time is 100 minutes. Then to know how much substance remain after 200 minutes the equation would be:

Substance remains= 1/2^(time/half-time) x substance initial mass
Substance remains = 1/2^(200 minutes/100minutes) x 1 times= 1/4 times