Below the raw deobfuscated data. 100% probability to get the "10% off".

                "segmentValuesArray": [{
                    "probability": 100,
                    "type": "string",
                    "value": "10% off exams",
                    "win": true,
                    "userData": {
                        "wheel_text_win_title": "Hurrah! You've hit 10% off exams. Lucky day!",
                        "wheel_text_win_description": "Please make sure to copy the following discount code to be able to use it on checkout.",
                        "wheel_coupon": "ITCareers10",
                        "wheel_text_coupon_button": "Continue & use discount"
                    }
                }, {
                    "probability": 0,
                    "type": "string",
                    "value": "Almost",
                    "win": false
                }, {
                    "probability": 0,
                    "type": "string",
                    "value": "15% off exams",
                    "win": true,
                    "userData": {
                        "wheel_text_win_title": "Hurrah! You've hit 15% off exams. Lucky day!",
                        "wheel_text_win_description": "Please make sure to copy the following discount code to be able to use it on checkout.",
                        "wheel_coupon": null,
                        "wheel_text_coupon_button": "Continue & use discount"
                    }
                }, {
                    "probability": 0,
                    "type": "string",
                    "value": "No luck today",
                    "win": false
                }, {
                    "probability": 0,
                    "type": "string",
                    "value": "20% off exams",
                    "win": true,
                    "userData": {
                        "wheel_text_win_title": "Hurrah! You've hit 20% off exams. Lucky day!",
                        "wheel_text_win_description": "Please make sure to copy the following discount code to be able to use it on checkout.",
                        "wheel_coupon": null,
                        "wheel_text_coupon_button": "Continue & use discount"
                    }
                }, {
                    "probability": 0,
                    "type": "string",
                    "value": "Next time",
                    "win": false
                }, {
                    "probability": 0,
                    "type": "string",
                    "value": "25% off exams",
                    "win": true,
                    "userData": {
                        "wheel_text_win_title": "Hurrah! You've hit 25% off exams. Lucky day!",
                        "wheel_text_win_description": "Please make sure to copy the following discount code to be able to use it on checkout.",
                        "wheel_coupon": null,
                        "wheel_text_coupon_button": "Continue & use discount"
                    }
                }, {
                    "probability": 0,
                    "type": "string",
                    "value": "Nope",
                    "win": false
                }, {
                    "probability": 0,
                    "type": "string",
                    "value": "30% off exams",
                    "win": true,
                    "userData": {
                        "wheel_text_win_title": "Hurrah! You've hit 30% off exams. Lucky day!",
                        "wheel_text_win_description": "Please make sure to copy the following discount code to be able to use it on checkout.",
                        "wheel_coupon": null,
                        "wheel_text_coupon_button": "Continue & use discount"
                    }
                }, {
                    "probability": 0,
                    "type": "string",
                    "value": "Sorry!",
                    "win": false
                }, {
                    "probability": 0,
                    "type": "string",
                    "value": "35% off exams",
                    "win": true,
                    "userData": {
                        "wheel_text_win_title": "Hurrah! You've hit 35% off exams. Lucky day!",
                        "wheel_text_win_description": "Please make sure to copy the following discount code to be able to use it on checkout.",
                        "wheel_coupon": null,
                        "wheel_text_coupon_button": "Continue & use discount"
                    }
                }, {
                    "probability": 0,
                    "type": "string",
                    "value": "Nothing",
                    "win": false
                }],

Thanks for that info. I figured it was heavily weighted for the 10% off but it appears it was the only possibility. I tested 10 for 10 before giving up.