SOLUTION: 80% of the red hat society is over 65 years old. 80% of those over 65 years old are also over 75 years old. How many members are over 75 years old if 240 members are between 65 and

Algebra ->  Percentage-and-ratio-word-problems -> SOLUTION: 80% of the red hat society is over 65 years old. 80% of those over 65 years old are also over 75 years old. How many members are over 75 years old if 240 members are between 65 and      Log On


   



Question 1070580: 80% of the red hat society is over 65 years old. 80% of those over 65 years old are also over 75 years old. How many members are over 75 years old if 240 members are between 65 and 75 years old?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +x+ = total members of the red hat society
+.8x+ = those over 65 yrs old
+.8%2A%28+.8x+%29+=+.64x+ = those over 75 yrs old
-----------------------------------------------
given:
+.8x+-+.64x+=+240+
+.16x+=+240+
+x+=+1500+
and
+.64x+=+.64%2A1500+
+.64x+=+960+
-----------------------
960 members are over 75
-----------------------
check:
Those under 65:
+x+-+.8x+=+.2x+
+.2x+=+.2%2A1500+
+.2x+=+300+
---------------------
Those 65 - 75:
+.8x+-+.64x+=+.16x+
+.16x+=+.16%2A1500+
+.16x+=+240+
----------------------
Those over 75:
+.8%2A%28+.8x+%29+=+.64x+
+.64x+=+.64%2A1500+
+.64x+=+960+
----------------------
+300+%2B+240+%2B+960+=+1500+
OK