A first number plus twice a second number is 5. Twice the first number plus the second totals 13. Find the numbers.

Let a and b = the numbers we must find.

a + 2b = 5Equation A

2a + b = 13Equation B

We have a system of equations in two variables.

I will solve A for little a.

a + 2b = 5

a = 5 - 2b

Now I will plug 5 - 2b for a in B.

2(5 - 2b) + b = 13

10 - 4b + b = 13

-3b = 3

b = -1

To find a, replace b with -1 in EITHER A or B.

I will use Equation A.

a + 2b = 5

a + 2(-1) = 5

a - 2 = 5

a = 7

The two numbers are -1 and 7.

Understand?

answer: h

step-by-step explanation:

answer:   35 % is the probability of a late departure or an early arrival.

step-by-step explanation:

let l represents the late departure and e represents the early departure.

then, according to the question,

p(l) = 12 %,   p(e) = 27 % and = 4 %

and, we have to find out,

but, we know that,

which is the required equation that will use to find the probability of a late departure or an early departure.

therefore,   the probability of a late departure or an early arrival =   35 %