Tameena has 4 old coins : P, Q, R and S. Coin R is worth $ 2.5. Coin S is worth 2 times the value of coin R. Coin Q is worth 3 times the value of coin R. The four coins are worth ` $40 altogether. What is the value of coin P ?

Question

( A ) 10
( B ) 15
( C ) 25
( D ) 30