College Algebra Math word problem?

Comments

• sue

  May 2021

  let n= #nickels so 0.05n= value of the nickels

  let d= # dimes so 0.10d= value of the dimes

  let q =# quarters so 0.25q = value of the quarters

  We are told that d=2q

  and n = d + 7 so n = 2q +7 We will use these facts to replace n and d

  we know 0.05n + 0.10d + 0.25q = 3.10

  so 0.05(2q +7) + 0.10(2q) + 0.25q = 3.10

  0.10q + 0.35 + 0.20q +0.25g = 3.10

  0.55q = 2.75

  q=5 quarters

  d= 2(5)= 10 dimes

  n= 2(5) + 7 = 17 nickels

  295 = (r + 14)t and 225 = rt

  295= rt + 14t

  295 = rt + 14t

  -225=-rt

  -------------------

  70 = 14t

  t= 5 hrs

  225 = r*5

  r= 45mph for the freight train

  45 +14 = 59 mph for the passenger train
• peabody

  May 2021

  Let x = number quarters

  So 2x = number of dimes //// There are twice as many dimes as quarters

  & (2x+7) = number of nickels ///// There are seven more nickels than dimes

  5(2x+7) + 10(2x) + 25x = 310

  10x +35 +20x +25x = 310

  55x = 310 -35

  55x = 275

  x = 275/55 = 5

  There are 5 quarters , 10 dimes & 27 nickels.

  Let v = speed of freight train

  Use d = vt

  so 225 = vt (1)

  Speed of passenger train is (v+14) mph

  so 295 = (v+14)t (2)

  295 = vt + 14t

  295 = 225 + 14t /// from (1) vt =225

  70 = 14t

  t = 70/14 = 5 hours

  Train speeds;

  Freight train = d/t = 225/5 = 45 mph

  Passengar = 45 + 14 = 59 mph

  Or do it this way

  295/5 = 59 mph
• zylch

  May 2021

  1) let n = nickels, d = dimes, and q = quarters

  d = 2q --> 1/2d = q

  n = 7 + d

  3.10 = .1d + .05n + .25q

  --> 3.10 = .1d + .05(7+d) + .25(d/2)

  --> 310 = 10d + 35 + 5d + 25/2d

  --> 275 = 27.5d

  --> d = 10

  --> n = 17

  --> q = 5

  17 nickels, 10 dimes, 5 quarters

  2) d = rt

  --> 295/(rp) = 225/(rf)

  --> rp = rf + 14

  --> 295(rf) = 225(rf + 14)

  --> 70(rf) = 3150

  --> rf = 45

  --> rp = 59

  Passenger Train = 59mph, Freight Train = 45mph
• harley-rogers_60affea5e1972

  May 2021

  let x = no. of quaters

  2x=dimes

  2x+7=nickels

  x(25)+x2(10)+(2x+7)(5)=3.10

  25x+20x+10x+35=3.10

  55x=275

  x=5...

  295/x+14=225/x

  70x=3150

  x=45

  that's probably right tho