It depends on what you are trying to calculate but the most common way I go to find percentage is to multiply by the number in decimal for ie. 50% = .5.
If you are looking for a way to do it quickly in your head I always take find out what 10% is like in the case of 100 it would be 10 so if I want to find 15% I know I can find 10% and if I cut what 10% is in half I will find 5% so likewise if I add what 10%+5% I will end up with 15%. For example, 10% of 100 is 10 half of 10 is 5 and 10+5 equals 15. If you need to find something like 20% or 30% I know that I can find 10% and instead of dividing(cutting it in half) I can multiply by 2 or 3. 10% + 10% =20%
I hope it helps, if you have more questions let me know!
Answer:
Q 12 roots of the equation

∝ = 
β = 
no matter if u oppose the root
(i) 2(
)
+2
(
)+2(
(ii)(
- 3 (
)(
) + (
) = 
Q 13 roots of equation

the roots of the second equation are
x1 = 1/3(-0.693) = -0.231
x2 = 1/3(1.443) = 0.481
the equation is
(x+0.231)(x-0.481)=0

Answer and Step-by-step explanation:
The computation is shown below;
As we know that
The simple interest is
Simple interest = Principal × rate × time
For Account A, the principal would be
2 = Principal × 3.2% × 3
So, the principal is $20.83
For account B, the principal would be
38.50 = Principal × 2.2% × 30
So, the principal is $58.33
Now the interest for both the accounts are as follows
For account 1
= $20.83 × 3.2%
= $0.67
And, for the account 2
= $58.33 × 2.2%
= $1.28
As it can be seen that the account 2 has the highest interest
The same is to be considered
This would be displayed as
3x/5