There are 40 coins in a bag, consisting of Rs. 5 and Rs. 2 coins. If the total amount is Rs. 140, how many Rs. 2 and Rs. 5 coins are there in the bag?

40 Rs 2 coins equal to Rs 80.and this amounts 140— 80= Rs60.if i exchange one Rs 2 by one Rs 5 balance amount decreases by Rs3.For exhausting Rs 60 i shall have to exchange 60/3=20 Rs 2 coins.Thus 20 Rs 5 coin shallb there.ans.

Step-by-step explanation:

answer not mine but hopefully it helps

x =-.20752

step-by-step explanation:

4^(x+2)=12

4^(x+2)=12

take the log base 4 on each side

log 4 (4^(x+2) = log 4(12)

we know log b(a^y) = y log b (a)

(x+2) log 4(4) = log 4 (12)

x+2 = log 4 (12)

we know   logb c = loga c/loga b

we want to convert to base 10   so a = 10

by default, we do not write the 10   c = 4   and b = 10

log4 10 = log 12/log 4

log4 10 = log 12/ log 4

x+2 = log 12/ log 4

subtract 2 from each side

x +2 -2 = log 12/ log 4 -2

x = 1.79248125 -2

x =-.20752