Average of 4 numbers, if the numbers are x,y,z,t then the average is (x+y+z+t)/4=average so
average=98
if 3 of the numbers are 86, 87 and 91 then what is the fourth number
assign
x=86
y=87
z=unknown
91=t
(86+87+z+91)/4=98
do parenthasees first
(264+z)/4=98
multiply both sides by 4 to get rid of fraciton
264+z=392
subtract 264 from both sides
z=128
the fourth number=128
3/4 is 75%
for this think of them as quarters 4 quarters is 100 %, 2 quarters is 50% so 3 quarters would be 75%
or you could just do 3 divided by 4 then times that by 100
2 49/100 in decimal form is 2.49 because a decimal in the one hundredths would be like this: 0.09 or 0.49, and the two is a whole number, so it would go before the decimal like this: 2.09 or 2.49.
Hope this helped:):)
Answer:
28 + 30 + 42 = 100
Step-by-step explanation:
s=small number
s+ (s+2) + (s+2 +12) =100
3s +16 = 100
3s =84
s = 28
small 28
mediam 28+2 = 30
large 30+12 = 42
Lucia can afford 11 hours of lessons
Second one is 2.7
