45. These word problems often seem to be two equations in two unknowns, here <em>h</em> for hits and <em>m</em> for misses.
"After 30 tries" translates into
+5 for a hit, -10 for a miss, John lost 90 translates to
We have
Answer: 14
Check: 5(14)-10(16)=-90, good
46. We have to make the odd assumption the grocer sells for his cost, but let's not beat up the question too hard.
Again, two unknowns, <em>b</em> kilograms of Brazil nuts and <em>c</em> kilograms of cashews.
<em>... sold 12 kg of the mixture ...</em>
<em>... cashews $8/kg and Brazil nuts $10/kg and the results is $8.50/kg ...</em>
This one's a bit more involved to translate because we have to recognize the total price is the 8.50 per kg times 12 kg.
The solving is pretty much just like the last one; we eliminate the unknown we're not asked for.
Answer: 9
Check: (9(8)+10(3))/12=102/12 = 8.50 good