Acollection of nickels and dimes is worth $6.10. there are 67 coins in all. how many nickels are there? 12, 18, 49 or 55 allan and dave bowl together and their combined total score for one game was 375 points. allan’s score was 60 less than twice dave’s. what were their score? dave: 145 allan: 230 dave: 160 allan: 215 dave: 215 allan: 160 dave: 230 allan: 145

 Question 1:

 For this case, the first thing we must do is define variables.
 We have then:
 x: number of nickels
 y: number of dimes
 We write the system of equations that adapts to the problem.
 We have then:
 0.05x + 0.10y = 6.10
 x + y = 67
 Solving the system we have:
 x = 12
 y = 55
 
 there are 12 nickels

 Question 2:

 For this case, the first thing we must do is define variables.
 We have then:
 x: Allan's score
 y: Dave's score
 We write the system of equations that adapts to the problem.
 We have then:
 x + y = 375
 x = 2y-60
 Solving the system we have:
 x = 230
 y = 145
 
 Dave: 145 Allan: 230

Ican't do any of the other stuff, but i can get you started. the answer, i believe, is $2.50.