Antonio has budgeted an average of $45 a month for entertainment. For the first five months of the year he has spent $48, $39, $60, $48, and $33. How much can Antonio spend in the sixth month without exceeding his average budget?

Question

amistre64 · Answer

sum(48,39,60,48,33) + x
----------------------- = 45
             6

lets call the sum S

S + x
----- = 45
    6

S + x = 45(6)

x = 45(6) - S

amistre64 · Answer

and if i did it right; I get $42 ?

anonymous · Answer

hmm its wronq :/

amistre64 · Answer

dbl check:

(48+39+60+48+33+x)/6 = 45

(48+39+60+48+33+42)/6 = 45

270/6 = 45

45 = 45

amistre64 · Answer

45*6 = 270

270 - (48+39+60+48+33) = 42

no matter how I do it; its always 42

amistre64 · Answer

another way is to see what he has spent like this:

$48 =   3 over 
$39 =   6 under
$60 = 15 over
$48 =   3 over
$33 = 12 under

3 - 6 = -3 +15 = 12 +3 = 15 -12 = 3

hes 3 bucks over at the moment;  45-3 = 42 dollars to get back on track