21. Carol scored 40 points higher on the math portion of the SAT test than on the language portion. If her total score for both parts was 1260, what was her score on each part?
Ans.
m= math
l=language
m=40l
total score=1260
m+l=1260
1260/2=630
In math’s,
630+20=650
And in language,
650-40=610

22. How many pounds of cashews selling at $4.00 per pound should be mixed with 3 pounds of peanuts selling at $1.60 per pound to make a mixture selling for $2.80 per pound?
Ans.
$1.60/$4.00=0.4pounds×3=1.2lb

23. The cost C for hiring a bulldozer and its operator is given by C=90h+150, where h is the number of hours that the bulldozer is hired. If the total cost is $510, for how many hours was the bulldozer hired?
Ans.
C=90h+150
Total cost is $510 find the number of hours,
C=510
510=90h+150
360=90h
h=4