The quantity R, in grams, of a certain radioactive substance decreases according to the exponential decay model dRdt=−0.05R, where t is measured in seconds. During an experiment, a scientist determines that the rate of decay of a second substance with the quantity S, in grams, can be represented by a linear model dSdt=−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?