A mobile phone is available for $39000 cash or $17000 as down payment GMAT Problem-Solving

This is a GMAT Problem solving question. Here, the data given in the questions has to be analyzed to answer the question. Several areas of mathematics can be involved in the process. The way options are given is very close to correct answer, and normal guessing can lead to mistakes. Students need to understand the question properly and use proper methods to approach the answer.
Only one of the five options is correct.

plain interest SI = (P*R*T)/100
where P represents the main sum
R stands for interest rate, while T stands for time in years.

Now, the consumer is not paying interest on the 17,000 down payment. The amount that will accrue interest is the balance that must be paid over a five-month period.
Therefore, 39,000 - 17,000 = 22,000 represents the principal amount for which interest is being charged.
Pain cost this 22,000 a total of 5*4800, or 24,000. (Time is five months, thus as T is measured in years, T = 5/12.)

SI = 2000 hence
2000 = (P*R*T)/100
2000 = (22,000*R*5)/(100*12)
R = (2,000*12*100)/22,000*5 R = 21.81%

D is the correct choice.

This is a GMAT Problem solving question. Here, the data given in the questions has to be analyzed to answer the question. Several areas of mathematics can be involved in the process. The way options are given is very close to correct answer, and normal guessing can lead to mistakes. Students need to understand the question properly and use proper methods to approach the answer.
Only one of the five options is correct.

Using the simple interest formula:
SI = (P * R * T) / 100
where SI is the simple interest, P is the principal amount, R is the rate of interest per annum, and T is the time period in years.

We have the following information:
SI = 2000
P = 22000 (the principal amount for which interest is being charged)
T = 5/12 (since the time period is given in months, we need to convert it to years by dividing by 12)

Plugging in the values, we have:
2000 = (22000 * R * (5/12)) / 100

Simplifying the equation:
2000 = (22000 * R * 5) / (100 * 12)

Multiplying both sides by (100 * 12) to isolate R:
(2000 * 12 * 100) = (22000 * R * 5)
2400000 = 110000 * R
R = 2400000 / 110000
R ≈ 21.81%

Therefore, the correct answer is D: 21.81%.

This is a GMAT Problem solving question. Here, the data given in the questions has to be analyzed to answer the question. Several areas of mathematics can be involved in the process. The way options are given is very close to correct answer, and normal guessing can lead to mistakes. Students need to understand the question properly and use proper methods to approach the answer.
Only one of the five options is correct.
We know that the total amount paid under the installment plan is $41,000, which includes both the down payment and the monthly installments.
The total interest paid can be calculated by subtracting the cash price from the total amount paid:

Interest = Total amount paid - Cash price
Interest = $41,000 - $39,000 = $2,000.

Now, we can calculate the rate of interest per annum using the following formula:
Rate of interest per annum = (Interest / Principal amount) * (100 / Time in years)
In this case, the principal amount is $22,000 (the remaining amount for which interest is being charged), and the time is 5 months, which is equivalent to 5/12 years.

Rate of interest per annum = ($2,000 / $22,000) * (100 / (5/12))
Rate of interest per annum = (2000/22000) * (12/5) * 100
Rate of interest per annum ≈ 0.0909 * 2.4 * 100
Rate of interest per annum ≈ 21.82%

Therefore, the correct rate of interest per annum is approximately 21.82%.