Please answer this question fast in two muintues

The? half-life of a radioactive substance is 20 years. if you start with some amount of this? substance, what fraction will remain in 120 ? years

Data from 2005 for various age groups show that for each $100 increase in the median weekly income for whites, the median weekly income of blacks increases by $105. also, for workers of ages 25 to 54 the median weekly income for whites was $676 and for blacks was $527. (a) let w represent the median weekly income for whites and b the median weekly income for blacks, and write the equation of the line that gives b as a linear function of w. b = (b) when the median weekly income for whites is $760, what does the equation in (a) predict for the median weekly income for blacks?

Find the percent cost of the total spent on each equipment $36, fees $158, transportation $59 a. 14%, 62%, 23% b. 15%, 60%, 35% c. 10%, 70%, 20% d. 11%, 62%, 27%