Question : If $\cos A = \sin ^2A$, and $a \sin ^{12}A+b \sin ^{10}A+c \sin ^{8}A+ \sin ^{6}A=1$, then $a + b + c$?

Option 1: 7

Option 2: 8

Option 3: 9

Option 4: 6

Question : If $\frac{2}{3}$ of A = 75% of B = 0.6 of C, then $A:B:C$ is:

Option 1: $2:3:3$

Option 2: $3:4:5$

Option 3: $4:5:6$

Option 4: $9:8:10$

Question : If $a^2+b^2+c^2+84 = 4(a - 2b + 4c)$, then $\sqrt{ab - bc + ca}$ is equal to:

Option 1:  $4 \sqrt{10}$

Option 2: $\sqrt{10}$

Option 3: $5\sqrt{10}$

Option 4: $2\sqrt{10}$

Question : If $3P=2Q$ and $2Q=3R$, then what is $P:Q:R$?

Option 1: $6:9:1$

Option 2: $2:3:2$

Option 3: $4:6:9$

Option 4: $4:6:1$

Question : If $a + b = 10$ and $ab = 9$, then the value of $a - b$ is:

Option 1: 7

Option 2: 5

Option 3: 8

Option 4: 6