The device shows that in one week the total cost of the electrical energy used by the kettle is 97 p. 1kw h of electrical energy costs 17 p. calculate the length of time for which the kettle has been switched on during the weekthe device shows that in one week the total cost of the electrical energy used by the kettle is 97 p. 1kw h of electrical energy costs 17 p. calculate the length of time for which the kettle has been switched on during the weekthe device shows that in one week the total cost of the electrical energy used by the kettle is 97 p. 1kw h of electrical energy costs 17 p. calculate the length of time for which the kettle has been switched on during the weekthe device shows that in one week the total cost of the electrical energy used by the kettle is 97 p. 1kw h of electrical energy costs 17 p. calculate the length of time for which the kettle has been switched on during the weekthe device shows that in one week the total cost of the electrical energy used by the kettle is 97 p. 1kw h of electrical energy costs 17 p. calculate the length of time for which the kettle has been switched on during the week
