Respuesta :
Let's write down what we know:
a=50+b
b=30+c
After one hour:
(a+50)*2=-70+3*(c+50)
let's eliminate the brackets:
2a+100=-70+3c+150
2a+100=+3c+80
which is:
2a=-20+3c
substituting from a=50+b:
100+2b=-20+3c
substituting from b=30+c
100+2(30+c)=-20+3c
100+60+2c=-20+3c
160+20=3c-2c
180=c.
So we know that c is equal to 40, then b will be b=30+c
b=30+180=210.
So B had 210 miles initially.
a=50+b
b=30+c
After one hour:
(a+50)*2=-70+3*(c+50)
let's eliminate the brackets:
2a+100=-70+3c+150
2a+100=+3c+80
which is:
2a=-20+3c
substituting from a=50+b:
100+2b=-20+3c
substituting from b=30+c
100+2(30+c)=-20+3c
100+60+2c=-20+3c
160+20=3c-2c
180=c.
So we know that c is equal to 40, then b will be b=30+c
b=30+180=210.
So B had 210 miles initially.
Answer:
a=50+b
b=30+c
After one hour:
(a+50)*2=-70+3*(c+50)
let's eliminate the brackets:
2a+100=-70+3c+150
2a+100=+3c+80
which is:
2a=-20+3c
substituting from a=50+b:
100+2b=-20+3c
substituting from b=30+c
100+2(30+c)=-20+3c
100+60+2c=-20+3c
160+20=3c-2c
180=c.
So we know that c is equal to 40, then b will be b=30+c
b=30+180=210.
So B had 210 miles initially.