A dairy needs 392 gallons of milk containing 5% butterfat. How many gallons each of milk containing 6% butterfat and milk containing 2% butterfat must be used to obtain the desired 392 gallons?

Respuesta :

                       Qty                    %                       Qty * %

Solution 1:        x                 6% = 0.06        =      0.06x

Solution 2:    392 - x         2% = 0.02        =      0.02(392 - x)  = 7.84 - 0.02x

Mixture:          392              5% = 0.05        =     0.06x + 7.84 - 0.02x

                                                 392(0.05)   =    0.08x + 7.84

                                                           19.6   =    0.08x + 7.84

                                                          11.76   =    0.08x

                                                            147    =      x

Solution 2:  392 - x    = 392 - (147)   = 245

Answer: 147 gallons 6% and 245 gallons of 2%

{x*0.02+0.06y=392*0.05

{x+y=392, x=392-y

0.04y=11.76, y=294; x=392-294=98

There is need 98 gallons of milk with 2% butterfat and 294 gallons of milk with 6% butterfat