Notice that 50 minutes is twice the half-life.
After 25 minutes, half of the starting amount remains, so that 88g decays to 44g.
After another 25 minutes (a total of 50 minutes), the 44g will decay to 22g.
Answer:
A and c
Step-by-step explanation:
multiply the 3 to both parts of equation
from 2007 to 2012 is only 5 years, so we can see this as a compound interest with a rate of 1.2% per annum for 5 years, so

If triangles PQR and STU are similar then PQ corresponds to ST and PR corresponds to SU. Therefore, PQ/ST=PR/SU
Considering that, PQ= 7-x, ST= 13-x, PR= x²+5 and SU= x² +20
therefore, (7-x)/(13-x)= (x²+5)/(x²+20)
cross multiplying,
7x² +140-x³+20x =13x²+65-x³-5x
combining the like terms,
6x² +15x -75=0
solving for x,
x = 5/2 or -5