Answer:
a : b = 25 : 9
Step-by-step explanation:
(3a - 5b) : (3a + 5b) = 1 : 4
Product of extremes = product of means
(3a - 5b) *4 = (3a +5b) * 1 {Distributive property}
3a * 4 - 5b*4 = 3a + 5b
12a - 20b = 3a + 5b
Add 20b to both sides
12a = 3a + 5b + 20b
12a = 3a + 25b
Subtract 3a from both sides
12a - 3a = 25b
9a = 25b

a:b = 25 : 9
Answer:
The total number of pencils is 6
Step-by-step explanation:
According to the given scenario, the computation of the total number of pencils is as follows:
There are 18 students
And let us assume there is m mechanical pencils that put in each bag
also he put twice of the regular pencil
So if he put the 3 mechanical pencil
So, the total number of pencils is
= 3 × 2
= 6
As it twice of the regular pencil
hence, the total number of pencils is 6
Answer: 47 students
Step-by-step explanation:
430 students went on a trip with the majority of them going on buses.
7 students however, had to use cars.
The number of students who used buses are:
= 430 - 7
= 423 students
The number of students in each bus is:
= No. of students taking buses / no. of buses
= 423 / 9 buses
= 47 students