sam has 18 coins in his pocket that are either quarters or nickels. the total value of these coins is $3.90.let q represent the number of quarters and n represent the number of nickels. the following system of equations represents this situation: q+n=180.25q+0.05n=3.9 0how many quarters and nickels does sam have?

Atype of plant is introduced into an ecosystem and quickly begins to take over. a scientist counts the number of plants after mmonths and develops the equation p(m)= 19.3(1.089)^m to model the situation. most recently, the scientist counted 138 plants.assuming there are no limiting factors to the growth of the plants, about how many months have passed since the plants werefirst introduced? a)o 6.1b)0.6.6c)10 72d)o 23.1