All triangles have the same value, and all circles have the same value. What is the sum of two circles?
$\Delta + \bigcirc + \Delta + \bigcirc + \Delta + \bigcirc + \Delta = 21$
$\bigcirc + \Delta+\bigcirc+\Delta+\bigcirc + \Delta + \bigcirc = 16$
$\bigcirc + \bigcirc = \ \, ?$
+118667 4T + 3C = 21
3T + 4C = 16
Multiply the fist one by 3 and the second one by 4
12T+9C=63
12T+16C=64
Subtract the first one FROM the second one
7C = 1
C = 1/7
2C=2/7
check
4T+3/7 = 21
4T = 20 +4/7
T= 5 and 1/7
Put into the second equation
3*(5+1/7)+ 4(1/7)
=15+3/7 + 4/7
=16
Works perfectly.
