1. ## SI

A person spends a part of amount of $20,000 for buying. 40% of the remaining amount is given at 6% interest and the rest money is given at 10% interest. If the total interest the person gets is$1250, then what is the amount he used for buying?

2. I do not understand what you posted.

3. Originally Posted by bluffmaster.roy.007
A person spends a part of amount of $20,000 for buying. 40% of the remaining amount is given at 6% interest and the rest money is given at 10% interest. If the total interest the person gets is$1250, then what is the amount he used for buying?
Originally Posted by Wilmer
I do not understand what you posted.
My Interpretation

1. A person gets $20,000 2. This person then spends an amount of money 3. 40% of the remainder attracts 6% interest 4. 10% of the remainder (from step 2) attracts 10% interest. ---------- Let x be the amount he spends and y be the amount which gets interest$\displaystyle y = 20,000-x $40% of y gets 6% interest:$\displaystyle 0.4y(1.06)^n$60% of y gets 10% interest:$\displaystyle 0.6y(1.10)^n$0.4y(1.06)^n + 0.6y(1.10)^n = 1250 If we assume n is over one period of time (usually annually) so that will cancel$\displaystyle 0.424y+0.66y = 1250\displaystyle 1.084y = 1250\displaystyle
y = 1153.1365\displaystyle x = 20000-y = 20000-1153.1365 = \$18846.86$

4. Hello, bluffmaster.roy.007!

I interpreted it differently . . .

A person spends a part of amount of $20,000 for buying. 40% of the remaining amount is given at 6% interest and the rest of the money is given at 10% interest. If the total interest the person gets is$1250,
then what is the amount he used for buying?

The person has $20,000. He spend$\displaystyle x$dollars for buying. He has$\displaystyle 20,\!000-x$dollars remaining. 40% of this remainder is: .$\displaystyle 0.40(20,\!000-x)$dollars. This earns 6% interest: .$\displaystyle I_1 \:=\:(0.06)(0.40)(20,\!000-x)\:=\:480 - 0.024x$60% of the remainder is: .$\displaystyle 0.60(20,\!000-x)$dollars. This earns 10% interest: .$\displaystyle I_2 \:=\:(0.10)(0.60)(20,\!000-x) \:=\:1200 - 0.06x$The total interest is$1250: .$\displaystyle (480-0.024x) + (1200 - 0.06x) \:=\:1250$

We have: .$\displaystyle 0.084x \:=\:430 \quad\Rightarrow\quad x \:=\:\frac{430}{0.084} \:=\:5119.047619$

Therefore, he used $5,119.05 for buying. 5. ## alternate solution...... Mr sorobon is rite.......... lets see how eazy it is..........consider x be the amount remainin... that is x=20,000-amount used for buying. 40% of remaining amount x gets 6%interest that is......(0.4)(0.06)(x) and for second interest (0.6)(0.1)(x) together they make 1250$=0.024x+0.06x

x=1250/0.084=14880.1

so amount used for buying is 20,000-x

and that is 5119.9\$....