A plane is flying from city A to city B at m mph. Another plane flying from B to A travels at 50 mph faster than the first plane. The cities are R miles apart. If both planes depart at the same time, in terms of R and m, how far are they from city A when they pass?
A) (R/m)+50
B) (Rm/2m) -50
C)Rm/2m+50
D)R+50/m+50
E)m+50/R
THey are approaching each other at the sum of their rates which is
+
or
Since Time = , the time until they meet is
Time =
Since Distance = Rate×Time, the plane that left City A has gone
× miles
or
miles
You must learn to write algebraic fractions all on one line, since that answer
is not any of the choices listed. When you write fractions all on one line,
you must use this "(" to show where each numerator or denominator begins,
and this ")" to show where each numerator or denominator ends. The only
exception is when a numerator consists of just one number or just one letter.
That's the only time you don't need to put parentheses around numerators and
denominators.
The choices you gave above amount to these:
A) (R/m)+50 means this: +
B) (Rm/2m) -50 means this: ×× -
C)Rm/2m+50 means this: ×× +
D)R+50/m+50 means this: + +
E)m+50/R means this: +
The way to write the correct answer all on one line is (Rm)/(2m+50).
I think you meant C) to be that, but as you see without parentheses
to show where the numerator and denominator begin and end, it doesn't
mean at all.
Edwin