Answer:
A = 8%, B = 5%
Explanation:
Let
a=concentration of solution A (in percent)
b=concentration of solution B (in percent)
Given
2a+4b = 0.06*(2+4) ...........(1)
4a+2b = 0.07*(4+2) ...........(2)
2(1) - (2)
4a-4a +8b-2b = 6 (2*0.06-0.07)
6b = 6(0.05)
b = 0.05 .............(3)
Substitute (3) into (1) and solve for a
2a+4(0.05) = 0.36
2a = 0.16
a = 0.08