



 
Hi Avinash. I can get you started. Begin by assigning variable names to the unknowns: Let N = the number of nickels, D = the number of dimes, Q = the number of quarters. Then translate what you know into equations: "Mary has 48 coins made up of nickels, dimes and quarters" 48 = N + D + Q "with a total value of $5.10" 5.10 = 0.05N + 0.10D + 0.25Q "She has 4 more dimes than nickels and quarters combined." D = 4 + (N + Q) This gives you three equations in three unknowns. You are asked to solve it using a matrix. To do this, first rearrange the three equations into the form: The unknowns in this general form are denoted by x_{1}, x_{2}, ... x_{n} and the coefficients (a's and b's above) are the values given. In your case, N, D and Q would be x_{1} through x_{3}. In matrix form the system of equations above can be written as: Write us back if you are uncertain about how to solve this matrix equation. Stephen La Rocque.  


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