Answer:
Step-by-step explanation:
Given
7.2, a, b, 3 are in A.P
[tex]2a = 7.2+b[/tex]
[tex]b = 2a - 7.2[/tex]
as
a, b, 3 are also in A.P
[tex]2b\:=\:a\:+\:3[/tex]
Putting [tex]b = 2a - 7.2[/tex]
[tex]2\left(2a-7.2\right)=a+3[/tex]
[tex]4a-14.4=a+3[/tex]
[tex]\mathrm{Add\:}14.4\mathrm{\:to\:both\:sides}[/tex]
[tex]4a-14.4+14.4=a+3+14.4[/tex]
[tex]4a=a+17.4[/tex]
[tex]4a-a=a+17.4-a[/tex]
[tex]3a=17.4[/tex]
[tex]\mathrm{Divide\:both\:sides\:by\:}3[/tex]
[tex]\frac{3a}{3}=\frac{17.4}{3}[/tex]
[tex]a=5.8[/tex]
Now, plugging [tex]a=5.8[/tex] in [tex]b = 2a - 7.2[/tex]
[tex]b=2\left(5.8\right)-7.2[/tex]
[tex]b=2\cdot \:5.8-7.2[/tex]
[tex]b=11.6-7.2[/tex]
[tex]b=4.4[/tex]
Therefore,
