What is the correct value for "R-chart?" I have tried 3.1 and 3.10 but they are both wrong.

Valtec Electronics fills orders for its electronic components and parts by truck to customers through several distribution centers. A measure of its supply chain responsiveness is order fulfillment lead time, which is the number of days from when a company receives an order to when it is delivered to the customer. A distribution center manager has taken 20.0 samples of five orders each during the month and recorded the lead time for each as follows: Construct an x-chart in conjunction with an R-chart for order fulfillment lead time at Valtec Electronics and compute R and x. (Round answers to 2 decimal places, e.g. 52.75. Do not leave any answer field blank. Enter 0 for amounts.) R-chart UCL 6.55 LCL 0 x-chart 3.05 UCL 4.84 LCL 1.27