The quantity , in grams, of a certain radioactive substance decreases according to the exponential decay model (dR)/(dt) = - 0.05R where t is measured in secondsDuring an experiment, a scientist determines that the rate of decay of a second substance with the quantity Sin grams, can be represented by a linear model (dS)/(dt) = - 4 where t is measured in seconds. If at time t = 0, R(0) = 100 and S(0) = 125 , at what time t, in seconds, will there be equal quantities of both substances?