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:
2520 patterns
Step-by-step explanation:
In 'n' 10! ways, books can be arranged. But, there are also 5! permutation of blue books 'n1', 2! permutation of identical green books 'n2', and 3! permutation identical black books 'n3'.
Therefore, for non identical arrangements:
= 2520
Therefore, the books can be arranged on a shelf in 2520 patterns